Kylin 1.0: An <scp>ab‐initio</scp> density matrix renormalization group quantum chemistry program

Xie, Zhaoxuan; Song, Yinxuan; Peng, Fangwen; Li, Jianhao; Cheng, Yifan; Zhang, Lingzhi; Ma, Yingjin; Tian, Yingqi; Luo, Zhen; Ma, Hao

doi:10.1002/jcc.27085

Cited by 9 publications

(10 citation statements)

References 137 publications

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“…The UC-MRCI, WK-MRCI, FIC-MRCI, and SDSCI calculations are performed by using Xi’an-CI (development version) interfaced in the Beijing Density Functional (BDF) software (development version) . EC-MRCI denotes the spin-adapted version unless otherwise specified, and it has been integrated in Kylin (development version) . CASSCF MOs are used for MRCI calculations.…”

Section: Resultsmentioning

confidence: 99%

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Spin-Adapted Externally Contracted Multireference Configuration Interaction Method Based on Selected Reference Configurations

Song,

Huang,

Liu

et al. 2024

J. Phys. Chem. A

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As one kind of approximation of the full configuration interaction solution, the selected configuration interaction (sCI) methods have been shown to be valuable for large active spaces. However, the inclusion of dynamic correlation beyond large active spaces is necessary for more quantitative results. Since the sCI wave function can provide a compact reference for multireference methods, previously, we proposed an externally contracted multireference configuration interaction method using the sCI reference reconstructed from the density matrix renormalization group wave function [J. Chem. Theory Comput. 2018, 14, 4747−4755]. The DMRG2sCI-EC-MRCI method is promising for dealing with more than 30 active orbitals and large basis sets. However, it suffers from two drawbacks: spin contamination and low efficiency when using Slater determinant bases. To solve these problems, in this work, we adopt configuration state function bases and introduce a new algorithm based on the hybrid of tree structure for convenient configuration space management and the graphical unitary group approach for efficient matrix element calculation. The test calculation of naphthalene shows that the spin-adapted version could achieve a speed-up of 6.0 compared with the previous version based on the Slater determinant. Examples of dinuclear copper(II) compound as well as Ln(III) and An(III) complexes show that the sCI-EC-MRCI can give quantitatively accurate results by including dynamic correlation over sCI for systems with large active spaces and basis sets.

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Section: Resultsmentioning

confidence: 99%

“…68 EC-MRCI denotes the spin-adapted version unless otherwise specified, and it has been integrated in Kylin (development version). 69 CASSCF MOs are used for MRCI calculations. The MOs are visualized by Multiwfn (version 3.7).…”

Section: Generate the S And D Kernel Trees By Removing One Andmentioning

confidence: 99%

Spin-Adapted Externally Contracted Multireference Configuration Interaction Method Based on Selected Reference Configurations

Song,

Huang,

Liu

et al. 2024

J. Phys. Chem. A

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“…116 The MOs were converted between the two programs by Molecular Orbital Kit (MOKIT) (accessed December 24, 2022) to make sure of the comparability of the results. 117 The ec-MRCI and RR-family methods are implemented in the Kylin program 14 and started from the generated FCIDUMP file from BDF. The results are shown in Table 3, and computational details can be found in Table S2.…”

Section: Different Variants Of Renormalized-residue-based Mrcimentioning

confidence: 99%

“…111 Both spin-adapted MPS-MRCI and RR-MRCI were executed using the Kylin program. 14 Detailed information on these calculations is provided in the Supporting Information.…”

Section: Benchmark Tests: Impact Factors and Sizementioning

confidence: 99%

Renormalized-Residue-Based Multireference Configuration Interaction Method for Strongly Correlated Systems

Cheng,

2024

J. Chem. Theory Comput.

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The implementation of multireference configuration interaction (MRCI) methods in quantum systems with large active spaces is hindered by the expansion of configuration bases or the intricate handling of reduced density matrices (RDMs). In this work, we present a spin-adapted renormalized-residue-based MRCI (RR-MRCI) approach that leverages renormalized residues to effectively capture the entanglement between active and inactive orbitals. This approach is reinforced by a novel efficient algorithm, which also facilitates an efficient deployment of spin-adapted matrix product state MRCI (MPS-MRCI). The RR-MRCI framework possesses several advantages: (1) It considers the orbital entanglement and utilizes highly compressed MPS structure, improving computational accuracy and efficiency compared with internally contracted (ic) MRCI. (2) Utilizing small-sized buffer environments of a few external orbitals as probes based on quantum information theory, it enhances computational efficiency over MPS-MRCI and offers potential application to large molecular systems. (3) The RR framework can be implemented in conjunction with ic-MRCI, eliminating the need for highrank RDMs, by using distinct renormalized residues. We evaluated this method across nine diverse molecular systems, including Cu 2 O 2 2+ with an active space of (24e,24o) and two complexes of lanthanide and actinide with active space (38e,36o), demonstrating the method's versatility and efficacy.

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“…This explains why DMRG has been remarkably successful in describing the static correlation in the electronic structure calculations. Nowadays, state-of-art DMRG quantum chemistry implementation − can aptly describe the electronic structures of large active spaces with around 100 orbitals.…”

Section: Introductionmentioning

confidence: 99%

New Density Matrix Renormalization Group Approaches for Strongly Correlated Systems Coupled with Large Environments

Cheng

Song

et al. 2023

J. Chem. Theory Comput.

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Thanks to the high compression of the matrix product state (MPS) form of the wave function and the efficient site-by-site iterative sweeping optimization algorithm, the density matrix normalization group (DMRG) and its time-dependent variant (TD-DMRG) have been established as powerful computational tools in accurately simulating the electronic structure and quantum dynamics of strongly correlated molecules with a large number (101–2) of quantum degrees of freedom (active orbitals or vibrational modes). However, the quantitative characterization of the quantum many-body behaviors of realistic strongly correlated systems requires a further consideration of the interaction between the embedded active subsystem and the remaining correlated environment, e.g., a larger number (102–3) of external orbitals in electronic structure or infinite condensed-phase phononic modes in nucleus dynamics. To this end, we introduced three new post-DMRG and TD-DMRG approaches, namely (1) DMRG2sCI-MRCI and DMRG2sCI-ENPT by the reconstruction of selected configuration interaction (sCI) type of compact reference function from DMRG coefficients and the use of externally contracted MRCI (multireference configuration interaction) and Epstein–Nesbet perturbation theory (ENPT), without recourse to the expensive high order n-electron reduced density matrices (n-RDMs). (2) DMRG combined with RR-MRCI (renormalized residue-based MRCI), which improves the computational accuracy and efficiency of internally contracted (ic) MRCI by renormalizing the contracted bases with small-sized buffer environment(s) of a few external orbitals as probes based on quantum information theory. (3) HM (hierarchical mapping)-TD-DMRG in which a large environment is reduced to a small number of renormalized environmental modes (which accounts for the most vital system–environment interactions) through stepwise mapping transformation. These advances extend the efficacy of highly accurate DMRG/TD-DMRG computations to the quantitative characterization of the electronic structure and quantum dynamics in realistic strongly correlated systems coupled with large environments and are reviewed in this paper.

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Kylin 1.0: An ab‐initio density matrix renormalization group quantum chemistry program

Cited by 9 publications

References 137 publications

Spin-Adapted Externally Contracted Multireference Configuration Interaction Method Based on Selected Reference Configurations

Spin-Adapted Externally Contracted Multireference Configuration Interaction Method Based on Selected Reference Configurations

Renormalized-Residue-Based Multireference Configuration Interaction Method for Strongly Correlated Systems

New Density Matrix Renormalization Group Approaches for Strongly Correlated Systems Coupled with Large Environments

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