[ { "id": "authors:40f1f-6nk07", "collection": "authors", "collection_id": "40f1f-6nk07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210409-075340645", "type": "article", "title": "Externally Corrected CCSD with Renormalized Perturbative Triples (R-ecCCSD(T)) and the Density Matrix Renormalization Group and Selected Configuration Interaction External Sources", "author": [ { "family_name": "Lee", "given_name": "Seunghoon", "orcid": "0000-0003-3665-587X", "clpid": "Lee-Seunghoon" }, { "family_name": "Zhai", "given_name": "Huanchen", "orcid": "0000-0003-0086-0388", "clpid": "Zhai-Huanchen" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Umrigar", "given_name": "C. J.", "clpid": "Umrigar-Cyrus-J" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "We investigate the renormalized perturbative triples correction together with the externally corrected coupled-cluster singles and doubles (ecCCSD) method. We use the density matrix renormalization group (DMRG) and heat-bath CI (HCI) as external sources for the ecCCSD equations. The accuracy is assessed for the potential energy surfaces of H\u2082O, N\u2082, and F\u2082. We find that the triples correction significantly improves upon ecCCSD, and we do not see any instability of the renormalized triples with respect to dissociation. We explore how to balance the cost of computing the external source amplitudes against the accuracy of the subsequent CC calculation. In this context, we find that very approximate wave functions (and their large amplitudes) serve as an efficient and accurate external source. Finally, we characterize the domain of correlation treatable using the ecCCSD and renormalized triples combination studied in this work via a well-known wave function diagnostic.", "doi": "10.1021/acs.jctc.1c00205", "issn": "1549-9618", "publisher": "American Chemical Society", "publication": "Journal of Chemical Theory and Computation", "publication_date": "2021-06-08", "series_number": "6", "volume": "17", "issue": "6", "pages": "3414-3425" }, { "id": "authors:vf48m-26m86", "collection": "authors", "collection_id": "vf48m-26m86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201008-071750086", "type": "article", "title": "Ground State Electronic Energy of Benzene", "author": [ { "family_name": "Eriksen", "given_name": "Janus J.", "orcid": "0000-0001-8583-3842", "clpid": "Eriksen-J-J" }, { "family_name": "Anderson", "given_name": "Tyler A.", "clpid": "Anderson-Tyler-A" }, { "family_name": "Deustua", "given_name": "J. Emiliano", "clpid": "Deustua-J-E" }, { "family_name": "Ghanem", "given_name": "Khaldoon", "clpid": "Ghanem-Khaldoon" }, { "family_name": "Hait", "given_name": "Diptarka", "orcid": "0000-0003-1570-920X", "clpid": "Hait-D" }, { "family_name": "Hoffmann", "given_name": "Mark R.", "orcid": "0000-0001-6016-8620", "clpid": "Hoffmann-Mark-R" }, { "family_name": "Lee", "given_name": "Seunghoon", "orcid": "0000-0003-3665-587X", "clpid": "Lee-Seunghoon" }, { "family_name": "Levine", "given_name": "Daniel S.", "orcid": "0000-0001-8921-3659", "clpid": "Levine-D-S" }, { "family_name": "Magoulas", "given_name": "Ilias", "orcid": "0000-0003-3252-9112", "clpid": "Magoulas-I" }, { "family_name": "Shen", "given_name": "Jun", "clpid": "Shen-Jun" }, { "family_name": "Tubman", "given_name": "Norm M.", "orcid": "0000-0002-9577-8485", "clpid": "Tubman-N-M" }, { "family_name": "Whaley", "given_name": "K. Birgitta", "orcid": "0000-0002-7164-4757", "clpid": "Whaley-K-B" }, { "family_name": "Xu", "given_name": "Enhua", "clpid": "Xu-Enhua" }, { "family_name": "Yao", "given_name": "Yuan", "clpid": "Yao-Yuan" }, { "family_name": "Zhang", "given_name": "Ning", "clpid": "Zhang-Ning" }, { "family_name": "Alavi", "given_name": "Ali", "clpid": "Alavi-Ali" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" }, { "family_name": "Head-Gordon", "given_name": "Martin", "orcid": "0000-0002-4309-6669", "clpid": "Head-Gordon-M" }, { "family_name": "Liu", "given_name": "Wenjian", "orcid": "0000-0002-1630-3466", "clpid": "Liu-Wenjian" }, { "family_name": "Piecuch", "given_name": "Piotr", "orcid": "0000-0002-7207-1815", "clpid": "Piecuch-P" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Ten-no", "given_name": "Seiichiro L.", "clpid": "Ten-no-S-L" }, { "family_name": "Umrigar", "given_name": "C. J.", "clpid": "Umrigar-C-J" }, { "family_name": "Gauss", "given_name": "J\u00fcrgen", "clpid": "Gauss-J\u00fcrgen" } ], "abstract": "We report on the findings of a blind challenge devoted to determining the frozen-core, full configuration interaction (FCI) ground-state energy of the benzene molecule in a standard correlation-consistent basis set of double-\u03b6 quality. As a broad international endeavor, our suite of wave function-based correlation methods collectively represents a diverse view of the high-accuracy repertoire offered by modern electronic structure theory. In our assessment, the evaluated high-level methods are all found to qualitatively agree on a final correlation energy, with most methods yielding an estimate of the FCI value around \u2212863 mE_H. However, we find the root-mean-square deviation of the energies from the studied methods to be considerable (1.3 mE_H), which in light of the acclaimed performance of each of the methods for smaller molecular systems clearly displays the challenges faced in extending reliable, near-exact correlation methods to larger systems. While the discrepancies exposed by our study thus emphasize the fact that the current state-of-the-art approaches leave room for improvement, we still expect the present assessment to provide a valuable community resource for benchmark and calibration purposes going forward.", "doi": "10.1021/acs.jpclett.0c02621", "issn": "1948-7185", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry Letters", "publication_date": "2020-10-15", "series_number": "20", "volume": "11", "issue": "20", "pages": "8922-8929" }, { "id": "authors:1j9ez-1nn09", "collection": "authors", "collection_id": "1j9ez-1nn09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200221-073241981", "type": "article", "title": "Direct Comparison of Many-Body Methods for Realistic Electronic Hamiltonians", "author": [ { "family_name": "Williams", "given_name": "Kiel T.", "clpid": "Williams-Kiel-T" }, { "family_name": "Yao", "given_name": "Yuan", "clpid": "Yao-Yuan" }, { "family_name": "Li", "given_name": "Jia", "clpid": "Li-Jia" }, { "family_name": "Chen", "given_name": "Li", "clpid": "Chen-Li" }, { "family_name": "Shi", "given_name": "Hao", "clpid": "Shi-Hao" }, { "family_name": "Motta", "given_name": "Mario", "orcid": "0000-0003-1647-9864", "clpid": "Motta-Mario" }, { "family_name": "Niu", "given_name": "Chunyao", "clpid": "Niu-Chunyao" }, { "family_name": "Ray", "given_name": "Ushnish", "orcid": "0000-0002-1850-4691", "clpid": "Ray-Ushnish" }, { "family_name": "Guo", "given_name": "Sheng", "orcid": "0000-0002-1083-1882", "clpid": "Guo-Sheng" }, { "family_name": "Anderson", "given_name": "Robert J.", "clpid": "Anderson-Robert-J" }, { "family_name": "Li", "given_name": "Junhao", "clpid": "Li-Junhao" }, { "family_name": "Tran", "given_name": "Lan Nguyen", "clpid": "Tran-Lan-Nguyen" }, { "family_name": "Yeh", "given_name": "Chia-Nan", "clpid": "Yeh-Chia-Nan" }, { "family_name": "Mussard", "given_name": "Bastien", "clpid": "Mussard-Bastien" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Bruneval", "given_name": "Fabien", "clpid": "Bruneval-Fabien" }, { "family_name": "van Schilfgaarde", "given_name": "Mark", "clpid": "van-Schilfgaarde-Mark" }, { "family_name": "Booth", "given_name": "George H.", "clpid": "Booth-George-H" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" }, { "family_name": "Zhang", "given_name": "Shiwei", "clpid": "Zhang-Shiwei" }, { "family_name": "Gull", "given_name": "Emanuel", "orcid": "0000-0002-6082-1260", "clpid": "Gull-Emanuel" }, { "family_name": "Zgid", "given_name": "Dominika", "orcid": "0000-0003-4363-8285", "clpid": "Zgid-Dominika" }, { "family_name": "Millis", "given_name": "Andrew", "clpid": "Millis-Andrew-J" }, { "family_name": "Umrigar", "given_name": "Cyrus J.", "clpid": "Umrigar-Cyrus-J" }, { "family_name": "Wagner", "given_name": "Lucas K.", "orcid": "0000-0002-3755-044X", "clpid": "Wagner-Lucas-K" }, { "literal": "Simons Collaboration on the Many-Electron Problem" } ], "abstract": "A large collaboration carefully benchmarks 20 first-principles many-body electronic structure methods on a test set of seven transition metal atoms and their ions and monoxides. Good agreement is attained between three systematically converged methods, resulting in experiment-free reference values. These reference values are used to assess the accuracy of modern emerging and scalable approaches to the many-electron problem. The most accurate methods obtain energies indistinguishable from experimental results, with the agreement mainly limited by the experimental uncertainties. A comparison between methods enables a unique perspective on calculations of many-body systems of electrons.", "doi": "10.1103/PhysRevX.10.011041", "issn": "2160-3308", "publisher": "American Physical Society", "publication": "Physical Review X", "publication_date": "2020-01", "series_number": "1", "volume": "10", "issue": "1", "pages": "Art. No. 011041" }, { "id": "authors:fqbjr-p3f16", "collection": "authors", "collection_id": "fqbjr-p3f16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200115-105617962", "type": "article", "title": "Accurate many-body electronic structure near the basis set limit: Application to the chromium dimer", "author": [ { "family_name": "Li", "given_name": "Junhao", "clpid": "Li-Junhao" }, { "family_name": "Yao", "given_name": "Yuan", "clpid": "Yao-Yuan" }, { "family_name": "Holmes", "given_name": "Adam A.", "clpid": "Holmes-A-A" }, { "family_name": "Otten", "given_name": "Matthew", "clpid": "Otten-M" }, { "family_name": "Sun", "given_name": "Qiming", "orcid": "0000-0003-0528-6186", "clpid": "Sun-Qiming" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Umrigar", "given_name": "C. J.", "clpid": "Umrigar-C-J" } ], "abstract": "We describe a method for computing near-exact energies for correlated systems with large Hilbert spaces. The method efficiently identifies the most important basis states (Slater determinants) and performs a variational calculation in the subspace spanned by these determinants. A semistochastic approach is then used to add a perturbative correction to the variational energy to compute the total energy. The size of the variational space is progressively increased until the total energy converges to within the desired tolerance. We demonstrate the power of the method by computing a near-exact potential energy curve for a very challenging molecule: the chromium dimer.", "doi": "10.1103/physrevresearch.2.012015", "issn": "2643-1564", "publisher": "American Physical Society", "publication": "Physical Review Research", "publication_date": "2020-01", "series_number": "1", "volume": "2", "issue": "1", "pages": "Art. No. 012015" }, { "id": "authors:rz1tn-3zg27", "collection": "authors", "collection_id": "rz1tn-3zg27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170206-112450918", "type": "article", "title": "The Python-based Simulations of Chemistry Framework (PySCF)", "author": [ { "family_name": "Sun", "given_name": "Qiming", "orcid": "0000-0003-0528-6186", "clpid": "Sun-Qiming" }, { "family_name": "Berkelbach", "given_name": "Timothy C.", "orcid": "0000-0002-7445-2136", "clpid": "Berkelbach-T-C" }, { "family_name": "Blunt", "given_name": "Nick S.", "clpid": "Blunt-N-S" }, { "family_name": "Booth", "given_name": "George H.", "clpid": "Booth-G-H" }, { "family_name": "Guo", "given_name": "Sheng", "orcid": "0000-0002-1083-1882", "clpid": "Guo-Sheng" }, { "family_name": "Li", "given_name": "Zhendong", "orcid": "0000-0002-0683-6293", "clpid": "Li-Zhendong" }, { "family_name": "Liu", "given_name": "Junzi", "clpid": "Liu-Junzi" }, { "family_name": "McClain", "given_name": "James D.", "clpid": "McClain-J-D" }, { "family_name": "Sayfutyarova", "given_name": "Elvira R.", "orcid": "0000-0001-8403-5013", "clpid": "Sayfutyarova-E-R" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Wouters", "given_name": "Sebastian", "clpid": "Wouters-S" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "Python-based simulations of chemistry framework (PySCF) is a general-purpose electronic structure platform designed from the ground up to emphasize code simplicity, so as to facilitate new method development and enable flexible computational workflows. The package provides a wide range of tools to support simulations of finite-size systems, extended systems with periodic boundary conditions, low-dimensional periodic systems, and custom Hamiltonians, using mean-field and post-mean-field methods with standard Gaussian basis functions. To ensure ease of extensibility, PySCF uses the Python language to implement almost all of its features, while computationally critical paths are implemented with heavily optimized C routines. Using this combined Python/C implementation, the package is as efficient as the best existing C or Fortran-based quantum chemistry programs. In this paper, we document the capabilities and design philosophy of the current version of the PySCF package.", "doi": "10.1002/wcms.1340", "issn": "1759-0876", "publisher": "John Wiley & Sons", "publication": "Wiley Interdisciplinary Reviews: Computational Molecular Science", "publication_date": "2018-01", "series_number": "1", "volume": "8", "issue": "1", "pages": "Art. No. e1340" }, { "id": "authors:z4xdt-stk25", "collection": "authors", "collection_id": "z4xdt-stk25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170914-110138411", "type": "article", "title": "Multistate Complete-Active-Space Second-Order Perturbation Theory Based on Density Matrix Renormalization Group Reference States", "author": [ { "family_name": "Yanai", "given_name": "Takeshi", "clpid": "Yanai-Takeshi" }, { "family_name": "Saitow", "given_name": "Masaaki", "clpid": "Saitow-Masaaki" }, { "family_name": "Xiong", "given_name": "Xiao-Gen", "clpid": "Xiong-Xiao-Gen" }, { "family_name": "Chalupsk\u00fd", "given_name": "Jakub", "clpid": "Chalupsk\u00fd-J" }, { "family_name": "Kurashige", "given_name": "Yuki", "orcid": "0000-0003-4652-8153", "clpid": "Kurashige-Yuki" }, { "family_name": "Guo", "given_name": "Sheng", "orcid": "0000-0002-1083-1882", "clpid": "Guo-Sheng" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" } ], "abstract": "We present the development of the multistate multireference second-order perturbation theory (CASPT2) with multiroot references, which are described using the density matrix renormalization group (DMRG) method to handle a large active space. The multistate first-order wave functions are expanded into the internally contracted (IC) basis of the single-state single-reference (SS-SR) scheme, which is shown to be the most feasible variant to use DMRG references. The feasibility of the SS-SR scheme comes from two factors: first, it formally does not require the fourth-order transition reduced density matrix (TRDM) and second, the computational complexity scales linearly with the number of the reference states. The extended multistate (XMS) treatment is further incorporated, giving suited treatment of the zeroth-order Hamiltonian despite the fact that the SS-SR based IC basis is not invariant with respect to the XMS rotation. In addition, the state-specific fourth-order reduced density matrix (RDM) is eliminated in an approximate fashion using the cumulant reconstruction formula, as also done in the previous state-specific DMRG-cu(4)-CASPT2 approach. The resultant method, referred to as DMRG-cu(4)-XMS-CASPT2, uses the RDMs and TRDMs of up to third-order provided by the DMRG calculation. The multistate potential energy curves of the photoisomerization of diarylethene derivatives with CAS(26e,24o) are presented to illustrate the applicability of our theoretical approach.", "doi": "10.1021/acs.jctc.7b00735", "issn": "1549-9618", "publisher": "American Chemical Society", "publication": "Journal of Chemical Theory and Computation", "publication_date": "2017-10-10", "series_number": "10", "volume": "13", "issue": "10", "pages": "4829-4840" }, { "id": "authors:dbfyc-9gy44", "collection": "authors", "collection_id": "dbfyc-9gy44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170106-091348676", "type": "article", "title": "The ab-initio density matrix renormalization group in practice", "author": [ { "family_name": "Olivares-Amaya", "given_name": "Roberto", "clpid": "Olivares-Amaya-R" }, { "family_name": "Hu", "given_name": "Weifeng", "clpid": "Hu-Weifeng" }, { "family_name": "Nakatani", "given_name": "Naoki", "clpid": "Nakatani-Naoki" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Yang", "given_name": "Jun", "orcid": "0000-0001-8701-9297", "clpid": "Yang-Jun" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "The ab-initio density matrix renormalization group (DMRG) is a tool that can be applied to a wide variety of interesting problems in quantum chemistry. Here, we examine the density matrix renormalization group from the vantage point of the quantum chemistry user. What kinds of problems is the DMRG well-suited to? What are the largest systems that can be treated at practical cost? What sort of accuracies can be obtained, and how do we reason about the computational difficulty in different molecules? By examining a diverse benchmark set of molecules: \u03c0-electron systems, benchmark main-group and transition metal dimers, and the Mn-oxo-salen and Fe-porphine organometallic compounds, we provide some answers to these questions, and show how the density matrix renormalization group is used in practice.", "doi": "10.1063/1.4905329", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "2015-01-21", "series_number": "3", "volume": "142", "issue": "3", "pages": "Art. No. 034102" }, { "id": "authors:c901y-r9a12", "collection": "authors", "collection_id": "c901y-r9a12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170106-112949955", "type": "article", "title": "Advances in molecular quantum chemistry contained in the Q-Chem 4 program package", "author": [ { "family_name": "Shao", "given_name": "Yihan", "clpid": "Shao-Yihan" }, { "family_name": "Gan", "given_name": "Zhengting", "clpid": "Gan-Zhengting" }, { "family_name": "Epifanovsky", "given_name": "Evgeny", "clpid": "Epifanovsky-Evgeny" }, { "family_name": "Gilbert", "given_name": "Andrew T. B.", "clpid": "Gilbert-Andrew-T-B" }, { "family_name": "Wormit", "given_name": "Michael", "clpid": "Wormit-Michael" }, { "family_name": "Kussmann", "given_name": "Joerg", "clpid": "Kussmann-Joerg" }, { "family_name": "Lange", "given_name": "Adrian W.", "clpid": "Lange-Adrian-W" }, { "family_name": "Behn", "given_name": "Andrew", "clpid": "Behn-Andrew" }, { "family_name": "Deng", "given_name": "Jia", "clpid": "Deng-Jia" }, { "family_name": "Feng", "given_name": "Xintian", "clpid": "Feng-Xintian" }, { "family_name": "Ghosh", "given_name": "Debashree", "orcid": "0000-0003-0726-7878", "clpid": "Ghosh-Debashree" }, { "family_name": "Goldey", "given_name": "Matthew", "clpid": "Goldey-Matthew" }, { "family_name": "Horn", "given_name": "Paul R.", "clpid": "Horn-Paul-R" }, { "family_name": "Jacobson", "given_name": "Leif D.", "clpid": "Jacobson-Leif-D" }, { "family_name": "Kaliman", "given_name": "Ilya", "clpid": "Kaliman-Ilya" }, { "family_name": "Khaliullin", "given_name": "Rustam Z.", "clpid": "Khaliullin-Rustam-Z" }, { "family_name": "Ku\u015b", "given_name": "Tomasz", "clpid": "Ku\u015b-Tomasz" }, { "family_name": "Landau", "given_name": "Arie", "clpid": "Landau-Arie" }, { "family_name": "Liu", "given_name": "Jie", "clpid": "Liu-Jie" }, { "family_name": "Proynov", "given_name": "Emil I.", "clpid": "Proynov-Emil-I" }, { "family_name": "Rhee", "given_name": "Young Min", "clpid": "Rhee-Young-Min" }, { "family_name": "Richard", "given_name": "Ryan M.", "clpid": "Richard-Ryan-M" }, { "family_name": "Rohrdanz", "given_name": "Mary A.", "clpid": "Rohrdanz-Mary-A" }, { "family_name": "Steele", "given_name": "Ryan P.", "clpid": "Steele-Ryan-P" }, { "family_name": "Sundstrom", "given_name": "Eric J.", "clpid": "Sundstrom-Eric-J" }, { "family_name": "Woodcock", "given_name": "H. Lee", "clpid": "Woodcock-H-Lee" }, { "family_name": "Zimmerman", "given_name": "Paul M.", "clpid": "Zimmerman-Paul-M" }, { "family_name": "Zuev", "given_name": "Dmitry", "clpid": "Zuev-Dmitry" }, { "family_name": "Albrecht", "given_name": "Ben", "clpid": "Albrecht-Ben" }, { "family_name": "Alguire", "given_name": "Ethan", "clpid": "Alguire-Ethan" }, { "family_name": "Austin", "given_name": "Brian J.", "clpid": "Austin-Brian-J" }, { "family_name": "Beran", "given_name": "Gregory J. O.", "clpid": "Beran-Gregory-J-O" }, { "family_name": "Bernard", "given_name": "Yves A.", "clpid": "Bernard-Yves-A" }, { "family_name": "Berquist", "given_name": "Eric", "clpid": "Berquist-Eric" }, { "family_name": "Brandhorst", "given_name": "Kai", "clpid": "Brandhorst-Kai" }, { "family_name": "Bravaya", "given_name": "Ksenia B.", "clpid": "Bravaya-Ksenia-B" }, { "family_name": "Brown", "given_name": "Shawn T.", "orcid": "0000-0002-7566-8537", "clpid": "Brown-Shawn-T" }, { "family_name": "Casanova", "given_name": "David", "clpid": "Casanova-David" }, { "family_name": "Chang", "given_name": "Chun-Min", "clpid": "Chang-Chun-Min" }, { "family_name": "Chen", "given_name": "Yunqing", "clpid": "Chen-Yunqing" }, { "family_name": "Chien", "given_name": "Siu Hung", "clpid": "Chien-Siu-Hung" }, { "family_name": "Closser", "given_name": "Kristina D.", "clpid": "Closser-Kristina-D" }, { "family_name": "Crittenden", "given_name": "Deborah L.", "clpid": "Crittenden-Deborah-L" }, { "family_name": "Diedenhofen", "given_name": "Michael", "clpid": "Diedenhofen-Michael" }, { "family_name": "DiStasio", "given_name": "Robert A.", "clpid": "DiStasio-Robert-A" }, { "family_name": "Do", "given_name": "Hainam", "clpid": "Do-Hainam" }, { "family_name": "Dutoi", "given_name": "Anthony D.", "clpid": "Dutoi-Anthony-D" }, { "family_name": "Edgar", "given_name": "Richard G.", "clpid": "Edgar-Richard-G" }, { "family_name": "Fatehi", "given_name": "Shervin", "clpid": "Fatehi-Shervin" }, { "family_name": "Fusti-Molnar", "given_name": "Laszlo", "clpid": "Fusti-Molnar-Laszlo" }, { "family_name": "Ghysels", "given_name": "An", "clpid": "Ghysels-An" }, { "family_name": "Golubeva-Zadorozhnaya", "given_name": "Anna", "clpid": "Golubeva-Zadorozhnaya-Anna" }, { "family_name": "Gomes", "given_name": "Joseph", "clpid": "Gomes-Joseph" }, { "family_name": "Hanson-Heine", "given_name": "Magnus W. D.", "clpid": "Hanson-Heine-Magnus-W-D" }, { "family_name": "Harbach", "given_name": "Philipp H. P.", "clpid": "Harbach-Philipp-H-P" }, { "family_name": "Hauser", "given_name": "Andreas W.", "clpid": "Hauser-Andreas-W" }, { "family_name": "Hohenstein", "given_name": "Edward G.", "clpid": "Hohenstein-Edward-G" }, { "family_name": "Holden", "given_name": "Zachary C.", "clpid": "Holden-Zachary-C" }, { "family_name": "Jagau", "given_name": "Thomas-C.", "clpid": "Jagau-Thomas-C" }, { "family_name": "Ji", "given_name": "Hyunjun", "clpid": "Ji-Hyunjun" }, { "family_name": "Kaduk", "given_name": "Benjamin", "clpid": "Kaduk-B" }, { "family_name": "Khistyaev", "given_name": "Kirill", "clpid": "Khistyaev-K" }, { "family_name": "Kim", "given_name": "Jaehoon", "clpid": "Kim-Jaehoon" }, { "family_name": "Kim", "given_name": "Jihan", "clpid": "Kim-Jihan" }, { "family_name": "King", "given_name": "Rollin A.", "clpid": "King-R-A" }, { "family_name": "Klunzinger", "given_name": "Phil", "clpid": "Klunzinger-P" }, { "family_name": "Kosenkov", "given_name": "Dmytro", "clpid": "Kosenkov-D" }, { "family_name": "Kowalczyk", "given_name": "Tim", "clpid": "Kowalczyk-T" }, { "family_name": "Krauter", "given_name": "Caroline M.", "clpid": "Krauter-C-M" }, { "family_name": "Lao", "given_name": "Ka Un", "clpid": "Lao-Ka-Un" }, { "family_name": "Laurent", "given_name": "Ad\u00e8le D.", "clpid": "Laurent-A-D" }, { "family_name": "Lawler", "given_name": "Keith V.", "clpid": "Lawler-K-V" }, { "family_name": "Levchenko", "given_name": "Sergey V.", "clpid": "Levchenko-S-V" }, { "family_name": "Lin", "given_name": "Ching Yeh", "clpid": "Lin-Ching-Yeh" }, { "family_name": "Liu", "given_name": "Fenglai", "clpid": "Liu-Fenglai" }, { "family_name": "Livshits", "given_name": "Ester", "clpid": "Livshits-E" }, { "family_name": "Lochan", "given_name": "Rohini C.", "clpid": "Lochan-R-C" }, { "family_name": "Luenser", "given_name": "Arne", "clpid": "Luenser-A" }, { "family_name": "Manohar", "given_name": "Prashant", "clpid": "Manohar-P" }, { "family_name": "Manzer", "given_name": "Samuel F.", "clpid": "Manzer-S-F" }, { "family_name": "Mao", "given_name": "Shan-Ping", "clpid": "Mao-Shan-Ping" }, { "family_name": "Mardirossian", "given_name": "Narbe", "clpid": "Mardirossian-N" }, { "family_name": "Marenich", "given_name": "Aleksandr V.", "clpid": "Marenich-A-V" }, { "family_name": "Maurer", "given_name": "Simon A.", "clpid": "Maurer-S-A" }, { "family_name": "Mayhall", "given_name": "Nicholas J.", "clpid": "Mayhall-N-J" }, { "family_name": "Neuscamman", "given_name": "Eric", "clpid": "Neuscamman-E" }, { "family_name": "Oana", "given_name": "C. Melania", "clpid": "Oana-C-M" }, { "family_name": "Olivares-Amaya", "given_name": "Roberto", "clpid": "Olivares-Amaya-R" }, { "family_name": "O'Neill", "given_name": "Darragh P.", "clpid": "O'Neill-D-P" }, { "family_name": "Parkhill", "given_name": "John A.", "clpid": "Parkhill-J-A" }, { "family_name": "Perrine", "given_name": "Trilisa M.", "clpid": "Perrine-T-M" }, { "family_name": "Peverati", "given_name": "Roberto", "clpid": "Peverati-R" }, { "family_name": "Prociuk", "given_name": "Alexander", "clpid": "Prociuk-A" }, { "family_name": "Rehn", "given_name": "Dirk R.", "clpid": "Rehn-D-R" }, { "family_name": "Rosta", "given_name": "Edina", "clpid": "Rosta-E" }, { "family_name": "Russ", "given_name": "Nicholas J.", "clpid": "Russ-N-J" }, { "family_name": "Sharada", "given_name": "Shaama M.", "clpid": "Sharada-S-M" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Small", "given_name": "David W.", "clpid": "Small-D-W" }, { "family_name": "Sodt", "given_name": "Alexander", "clpid": "Sodt-A" }, { "family_name": "Stein", "given_name": "Tamar", "clpid": "Stein-T" }, { "family_name": "St\u00fcck", "given_name": "David", "clpid": "St\u00fcck-D" }, { "family_name": "Su", "given_name": "Yu-Chuan", "clpid": "Su-Yu-Chuan" }, { "family_name": "Thom", "given_name": "Alex J. W.", "clpid": "Thom-A-J-W" }, { "family_name": "Tsuchimochi", "given_name": "Takashi", "clpid": "Tsuchimochi-Takashi" }, { "family_name": "Vanovschi", "given_name": "Vitalii", "clpid": "Vanovschi-V" }, { "family_name": "Vogt", "given_name": "Leslie", "clpid": "Vogt-L" }, { "family_name": "Vydrov", "given_name": "Oleg", "clpid": "Vydrov-O" }, { "family_name": "Wang", "given_name": "Tao", "clpid": "Wang-Tao" }, { "family_name": "Watson", "given_name": "Mark A.", "clpid": "Watson-M-A" }, { "family_name": "Wenzel", "given_name": "Jan", "clpid": "Wenzel-J" }, { "family_name": "White", "given_name": "Alec", "clpid": "White-A" }, { "family_name": "Williams", "given_name": "Christopher F.", "clpid": "Williams-C-F" }, { "family_name": "Yang", "given_name": "Jun", "orcid": "0000-0001-8701-9297", "clpid": "Yang-Jun" }, { "family_name": "Yeganeh", "given_name": "Sina", "clpid": "Yeganeh-S" }, { "family_name": "Yost", "given_name": "Shane R.", "clpid": "Yost-S-R" }, { "family_name": "You", "given_name": "Zhi-Qiang", "clpid": "You-Zhi-Qiang" }, { "family_name": "Zhang", "given_name": "Igor Ying", "clpid": "Zhang-Igor-Ying" }, { "family_name": "Zhang", "given_name": "Xing", "clpid": "Zhang-Xing" }, { "family_name": "Zhao", "given_name": "Yan", "clpid": "Zhao-Yan" }, { "family_name": "Brooks", "given_name": "Bernard R.", "clpid": "Brooks-B-R" }, { "family_name": "Chan", "given_name": "Garnet K. L.", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" }, { "family_name": "Chipman", "given_name": "Daniel M.", "clpid": "Chipman-D-M" }, { "family_name": "Cramer", "given_name": "Christopher J.", "clpid": "Cramer-C-J" }, { "family_name": "Goddard", "given_name": "William A.", "orcid": "0000-0003-0097-5716", "clpid": "Goddard-W-A-III" }, { "family_name": "Gordon", "given_name": "Mark S.", "clpid": "Gordon-M-S" }, { "family_name": "Hehre", "given_name": "Warren J.", "clpid": "Hehre-W-J" }, { "family_name": "Klamt", "given_name": "Andreas", "clpid": "Klamt-A" }, { "family_name": "Schaefer", "given_name": "Henry F.", "clpid": "Schaefer-H-F-III" }, { "family_name": "Schmidt", "given_name": "Michael W.", "clpid": "Schmidt-M-W" }, { "family_name": "Sherrill", "given_name": "C. David", "clpid": "Sherrill-C-D" }, { "family_name": "Truhlar", "given_name": "Donald G.", "clpid": "Truhlar-D-G" }, { "family_name": "Warshel", "given_name": "Arieh", "clpid": "Warshel-A" }, { "family_name": "Xu", "given_name": "Xin", "clpid": "Xu-Xin" }, { "family_name": "Aspuru-Guzik", "given_name": "Al\u00e1n", "clpid": "Aspuru-Guzik-A" }, { "family_name": "Baer", "given_name": "Roi", "clpid": "Baer-R" }, { "family_name": "Bell", "given_name": "Alexis T.", "orcid": "0000-0002-5738-4645", "clpid": "Bell-A-T" }, { "family_name": "Besley", "given_name": "Nicholas A.", "clpid": "Besley-N-A" }, { "family_name": "Chai", "given_name": "Jeng-Da", "clpid": "Chai-Jeng-Da" }, { "family_name": "Dreuw", "given_name": "Andreas", "clpid": "Dreuw-Andreas" }, { "family_name": "Dunietz", "given_name": "Barry D.", "clpid": "Dunietz-B-D" }, { "family_name": "Furlani", "given_name": "Thomas R.", "clpid": "Furlani-T-R" }, { "family_name": "Gwaltney", "given_name": "Steven R.", "clpid": "Gwaltney-S-R" }, { "family_name": "Hsu", "given_name": "Chao-Ping", "clpid": "Hsu-Chao-Ping" }, { "family_name": "Jung", "given_name": "Yousung", "orcid": "0000-0003-2615-8394", "clpid": "Jung-Yousung" }, { "family_name": "Kong", "given_name": "Jing", "clpid": "Kong-Jing" }, { "family_name": "Lambrecht", "given_name": "Daniel S.", "clpid": "Lambrecht-Daniel-S" }, { "family_name": "Liang", "given_name": "WanZhen", "clpid": "Liang-WanZhen" }, { "family_name": "Ochsenfeld", "given_name": "Christian", "clpid": "Ochsenfeld-C" }, { "family_name": "Rassolov", "given_name": "Vitaly A.", "clpid": "Rassolov-V-A" }, { "family_name": "Slipchenko", "given_name": "Lyudmila V.", "clpid": "Slipchenko-L-V" }, { "family_name": "Subotnik", "given_name": "Joseph E.", "clpid": "Subotnik-J-E" }, { "family_name": "Van Voorhis", "given_name": "Troy", "clpid": "Van-Voorhis-T-A" }, { "family_name": "Herbert", "given_name": "John M.", "clpid": "Herbert-J-M" }, { "family_name": "Krylov", "given_name": "Anna I.", "orcid": "0000-0001-6788-5016", "clpid": "Krylov-A-I" }, { "family_name": "Gill", "given_name": "Peter M.W.", "clpid": "Gill-P-M-W" }, { "family_name": "Head-Gordon", "given_name": "Martin", "orcid": "0000-0002-4309-6669", "clpid": "Head-Gordon-M" } ], "abstract": "A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order M\u00f8ller\u2013Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr_2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.", "doi": "10.1080/00268976.2014.952696", "issn": "0026-8976", "publisher": "Taylor & Francis", "publication": "Molecular Physics", "publication_date": "2015", "series_number": "2", "volume": "113", "issue": "2", "pages": "184-215" }, { "id": "authors:xzxp2-7q641", "collection": "authors", "collection_id": "xzxp2-7q641", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170106-125839610", "type": "article", "title": "Low-energy spectrum of iron\u2013sulfur clusters directly from many-particle quantum mechanics", "author": [ { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Sivalingam", "given_name": "Kantharuban", "clpid": "Sivalingam-K" }, { "family_name": "Neese", "given_name": "Frank", "clpid": "Neese-F" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "Iron\u2013sulfur clusters are a universal biological motif. They carry out electron transfer, redox chemistry and even oxygen sensing, in diverse processes including nitrogen fixation, respiration and photosynthesis. Their low-lying electronic states are key to their remarkable reactivity, but they cannot be directly observed. Here, we present the first ever quantum calculation of the electronic levels of [2Fe\u20132S] and [4Fe\u20134S] clusters free from any model assumptions. Our results highlight the limitations of long-standing models of their electronic structure. In particular, we demonstrate that the widely used Heisenberg double exchange model underestimates the number of states by one to two orders of magnitude, which can conclusively be traced to the absence of Fe d -> d excitations, thought to be important in these clusters. Furthermore, the electronic energy levels of even the same spin are dense on the scale of vibrational fluctuations and this provides a natural explanation for the ubiquity of these clusters in catalysis in nature.", "doi": "10.1038/nchem.2041", "issn": "1755-4330", "publisher": "Nature Publishing Group", "publication": "Nature Chemistry", "publication_date": "2014-10", "series_number": "10", "volume": "6", "issue": "10", "pages": "927-933" }, { "id": "authors:x47by-hq071", "collection": "authors", "collection_id": "x47by-hq071", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170106-123434796", "type": "article", "title": "Communication: A flexible multi-reference perturbation theory by minimizing the Hylleraas functional with matrix product states", "author": [ { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "We describe a formulation of multi-reference perturbation theory that obtains a rigorous upper bound to the second order energy by minimizing the Hylleraas functional in the space of matrix product states (MPS). The first order wavefunctions so obtained can also be used to compute the third order energy with little overhead. Our formulation has several advantages including (i) flexibility with respect to the choice of zeroth order Hamiltonian, (ii) recovery of the exact uncontracted multi-reference perturbation theory energies in the limit of large MPS bond dimension, (iii) no requirement to compute high body density matrices, (iv) an embarrassingly parallel algorithm (scaling up to the number of virtual orbitals, squared, processors). Preliminary numerical examples show that the MPS bond dimension required for accurate first order wavefunctions scales sub-linearly with the size of the basis.", "doi": "10.1063/1.4895977", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "2014-09-21", "series_number": "11", "volume": "141", "issue": "11", "pages": "Art. No. 111101" }, { "id": "authors:pq8c6-ap112", "collection": "authors", "collection_id": "pq8c6-ap112", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170113-123256350", "type": "article", "title": "Intermediate and spin-liquid phase of the half-filled honeycomb Hubbard model", "author": [ { "family_name": "Chen", "given_name": "Qiaoni", "clpid": "Chen-Qiaoni" }, { "family_name": "Booth", "given_name": "George H.", "clpid": "Booth-G-H" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Knizia", "given_name": "Gerald", "orcid": "0000-0002-7163-4823", "clpid": "Knizia-Gerald" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "We obtain the phase diagram of the half-filled honeycomb Hubbard model with density matrix embedding theory, to address recent controversy at intermediate couplings. We use clusters from 2\u201312 sites and lattices at the thermodynamic limit. We identify a paramagnetic insulating state, with possible hexagonal cluster order, competitive with the antiferromagnetic phase at intermediate coupling. However, its stability is strongly cluster and lattice size dependent, explaining controversies in earlier work. Our results support the paramagnetic insulator as being a metastable, rather than a true, intermediate phase, in the thermodynamic limit.", "doi": "10.1103/PhysRevB.89.165134", "issn": "2469-9950", "publisher": "American Physical Society", "publication": "Physical Review B", "publication_date": "2014-04-15", "series_number": "16", "volume": "89", "issue": "16", "pages": "Art. No. 165134" }, { "id": "authors:45gjb-1gx62", "collection": "authors", "collection_id": "45gjb-1gx62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170113-131620432", "type": "article", "title": "Spectroscopic accuracy directly from quantum chemistry: Application to ground and excited states of beryllium dimer", "author": [ { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Yanai", "given_name": "Takeshi", "clpid": "Yanai-Takeshi" }, { "family_name": "Booth", "given_name": "George H.", "clpid": "Booth-G-H" }, { "family_name": "Umrigar", "given_name": "C. J.", "clpid": "Umrigar-C-J" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "We combine explicit correlation via the canonical transcorrelation approach with the density matrix renormalization group and initiator full configuration interaction quantum Monte Carlo methods to compute a near-exact beryllium dimer curve, without the use of composite methods. In particular, our direct density matrix renormalization group calculations produce a well-depth of De = 931.2 cm^(\u22121) which agrees very well with recent experimentally derived estimates De = 929.7\u00b12 cm^(\u22121) [J. M. Merritt, V. E. Bondybey, and M. C. Heaven, Science 324, 1548 (2009)] and De= 934.6 cm^(\u22121) [K. Patkowski, V. \u0160pirko, and K. Szalewicz, Science 326, 1382 (2009)], as well the best composite theoretical estimates, De = 938\u00b115 cm^(\u22121) [K. Patkowski, R. Podeszwa, and K. Szalewicz, J. Phys. Chem. A 111, 12822 (2007)] and De=935.1\u00b110 cm^(\u22121) [J. Koput, Phys. Chem. Chem. Phys. 13, 20311 (2011)]. Our results suggest possible inaccuracies in the functional form of the potential used at shorter bond lengths to fit the experimental data [J. M. Merritt, V. E. Bondybey, and M. C. Heaven, Science 324, 1548 (2009)]. With the density matrix renormalization group we also compute near-exact vertical excitation energies at the equilibrium geometry. These provide non-trivial benchmarks for quantum chemical methods for excited states, and illustrate the surprisingly large error that remains for 1 ^1\u03a3^(\u2212)_g state with approximate multi-reference configuration interaction and equation-of-motion coupled cluster methods. Overall, we demonstrate that explicitly correlated density matrix renormalization group and initiator full configuration interaction quantum Monte Carlo methods allow us to fully converge to the basis set and correlation limit of the non-relativistic Schr\u00f6dinger equation in small molecules.", "doi": "10.1063/1.4867383", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "2014-03-14", "series_number": "10", "volume": "140", "issue": "10", "pages": "Art. No. 104112" }, { "id": "authors:1y65g-cqf79", "collection": "authors", "collection_id": "1y65g-cqf79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170125-080044523", "type": "article", "title": "Spin-adapted density matrix renormalization group algorithms for quantum chemistry", "author": [ { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" }, { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" } ], "abstract": "We extend the spin-adapted density matrix renormalization group (DMRG) algorithm of McCulloch and Gulacsi [Europhys. Lett. 57, 852 (2002)]10.1209/epl/i2002-00393-0 to quantum chemical Hamiltonians. This involves using a quasi-density matrix, to ensure that the renormalized DMRG states are eigenfunctions of \u015c^2, and the Wigner-Eckart theorem, to reduce overall storage and computational costs. We argue that the spin-adapted DMRG algorithm is most advantageous for low spin states. Consequently, we also implement a singlet-embedding strategy due to Tatsuaki [Phys. Rev. E 61, 3199 (2000)]10.1103/PhysRevE.61.3199 where we target high spin states as a component of a larger fictitious singlet system. Finally, we present an efficient algorithm to calculate one- and two-body reduced density matrices from the spin-adapted wavefunctions. We evaluate our developments with benchmark calculations on transition metal system active space models. These include the Fe_2S_2, [Fe_2S_2(SCH_3)_4]^(2\u2212), and Cr_2 systems. In the case of Fe_2S_2, the spin-ladder spacing is on the microHartree scale, and here we show that we can target such very closely spaced states. In [Fe_2S_2(SCH_3)_4]^(2\u2212), we calculate particle and spin correlation functions, to examine the role of sulfur bridging orbitals in the electronic structure. In Cr_2 we demonstrate that spin-adaptation with the Wigner-Eckart theorem and using singlet embedding can yield up to an order of magnitude increase in computational efficiency. Overall, these calculations demonstrate the potential of using spin-adaptation to extend the range of DMRG calculations in complex transition metal problems.", "doi": "10.1063/1.3695642", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "2012-03-28", "series_number": "12", "volume": "136", "issue": "12", "pages": "Art. No. 124121" }, { "id": "authors:ba5th-dhe51", "collection": "authors", "collection_id": "ba5th-dhe51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170113-163528165", "type": "article", "title": "The Density Matrix Renormalization Group in Quantum Chemistry", "author": [ { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" } ], "abstract": "The density matrix renormalization group is a method that is useful for describing molecules that have strongly correlated electrons. Here we provide a pedagogical overview of the basic challenges of strong correlation, how the density matrix renormalization group works, a survey of its existing applications to molecular problems, and some thoughts on the future of the method.", "doi": "10.1146/annurev-physchem-032210-103338", "issn": "0066-426X", "publisher": "Annual Reviews", "publication": "Annual Review of Physical Chemistry", "publication_date": "2011-05", "volume": "62", "pages": "465-481" }, { "id": "authors:y4b3s-adr84", "collection": "authors", "collection_id": "y4b3s-adr84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170203-134344891", "type": "book_section", "title": "Solving Problems with Strong Correlation Using the Density Matrix Renormalization Group (DMRG)", "book_title": "Solving the Schr\u00f6dinger Equation", "author": [ { "family_name": "Chan", "given_name": "Garnet Kin-Lic", "orcid": "0000-0001-8009-6038", "clpid": "Chan-Garnet-K-L" }, { "family_name": "Sharma", "given_name": "Sandeep", "orcid": "0000-0002-6598-8887", "clpid": "Sharma-Sandeep" } ], "contributor": [ { "family_name": "Popelier", "given_name": "Paul", "clpid": "Popelier-P" } ], "abstract": "This chapter is concerned with the problem of strongly correlated electrons in quantum chemistry. We describe how a technique known as the density matrix renormalization group (DMRG) can tackle complicated chemical problems of strong correlation by capturing the local nature of the correlations. We analyse the matrix product state structure of the DMRG wavefunction that encodes one-dimensional aspects of locality. We also discuss the connection to the traditional ideas of the renormalization group. We finish with a survey of applications of the DMRG, its strengths and weaknesses in chemical applications, and its recent promising generalization to tensor network states.", "doi": "10.1142/9781848167254_0003", "isbn": "9781848167247", "publisher": "Imperial College Press", "place_of_publication": "London", "publication_date": "2011", "pages": "43-60" } ]