Efficient algorithm for multiconfiguration pair-density functional theory with application to the heterolytic dissociation energy of ferrocene

Sand, Andrew M.; Truhlar, Donald G.; Gagliardi, Laura

doi:10.1063/1.4973709

“…MC-PDFT generally produces results that are comparable in accuracy to complete active space second-order perturbation theory (CASPT2) but at significantly lower computa-tional cost 191 for bond energies, 59,60,177,192,193 spin-multiplet splittings, [194][195][196][197] and other excitation energies. [198][199][200][201] These results are summarized in a The reference wave function is optimized from a GASSCF calculation.…”

Section: Performance Of Mc-pdftmentioning

confidence: 99%

OpenMolcas: From Source Code to Insight

Galván

¹

,

Vacher

²

,

Alavi

³

et al. 2019

J. Chem. Theory Comput.

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In this article we describe the OpenMolcas environment and invite the computational chemistry community to collaborate. The open-source project already includes a large number of new developments realized during the transition from the commercial MOLCAS product to the open-source platform. The paper initially describes the technical details of the new software development platform. This is followed by brief presentations of many new methods, implementations, and features of the OpenMolcas program suite. These developments include novel wave function methods such as stochastic complete active space self-consistent field, density matrix renormalization group (DMRG) methods, and hybrid multiconfigurational

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“…While the (14,14) CASSCF singlet and triplet have 2760615 and 5010005 CSFs respectively, the corresponding LASSCF wavefunctions have only 353 and 351 CSFs. While the difference in LASSCF and LAS-PDFT are independent of the basis set size, the disagreement between LAS and CAS energies increases for a larger (14,14) active space, as expected based on the greater reduction in the CSFs.…”

Section: Stilbenementioning

confidence: 51%

“…We also tested the effect of changing the basis sets (6-31G(d) and 6-31+G(d)) and the size of the active space (a (14,14) active space) for the dihedral scan of stilbene (SI section S2). The (14,14) active space, which includes all the p and p* orbitals of stilbene, is decomposed in three active subspaces with a (6,6) subspace on each phenyl ring and a (2,2) subspace on the CH-CH unit. This leads to an even more drastic reduction in the cost.…”

Section: Stilbenementioning

confidence: 99%

Localized Active Space Pair-Density Functional Theory

Pandharkar

¹

,

Hermes

²

,

Cramer

³

et al. 2021

J. Chem. Theory Comput.

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Accurate quantum chemical methods for the prediction of spin-state energy gaps for strongly correlated systems are computationally expensive and scale poorly with the size of the system. This makes calculations for many experimentally interesting molecules impractical even with abundant computational resources. In previous work, we have shown that the localized active space (LAS) self-consistent field (SCF) method is an efficient way to obtain multi-configuration SCF wave functions of comparable quality to the corresponding complete active space (CAS) ones. To obtain quantitative results, a post-SCF method is needed to estimate the complete correlation energy. One such method is multiconfiguration pair-density functional theory (PDFT), which calculates the energy based on the density and on-top pair density obtained from a multiconfiguration wave function. In this work we introduce localized-active-space pair-density functional theory, which uses a LAS wave function for subsequent PDFT calculations. The method is tested for computing spin-state energy gaps in conjugated organic molecules and bimetallic compounds and is shown to give results within 0.05 eV of the corresponding CAS-PDFT results at a significantly lower cost. File list (2) download file view on ChemRxiv Localized_active_space_pair_density_functiona_theory... (594.23 KiB) download file view on ChemRxiv Localized_active_space_pair_density_functiona_theory.pdf (2.40 MiB)

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“…We also tested the effect of changing the basis sets (6-31G(d) and 6-31+G(d)) and the size of the active space (a (14,14) active space) for the dihedral scan of stilbene (SI section S2). The (14,14) active space, which includes all the p and p* orbitals of stilbene, is decomposed in three active subspaces with a (6,6) subspace on each phenyl ring and a (2,2) subspace on the CH-CH unit. This leads to an even more drastic reduction in the cost.…”

Section: Stilbenementioning

confidence: 99%

Localized Active Space Pair-Density Functional Theory

Pandharkar

¹

,

Hermes

²

,

Cramer³

et al. 2021

Preprint

Self Cite

0

View full text Add to dashboard Cite

Accurate quantum chemical methods for the prediction of spin-state energy gaps for strongly correlated systems are computationally expensive and scale poorly with the size of the system. This makes calculations for many experimentally interesting molecules impractical even with abundant computational resources. In previous work, we have shown that the localized active space (LAS) self-consistent field (SCF) method is an efficient way to obtain multi-configuration SCF wave functions of comparable quality to the corresponding complete active space (CAS) ones. To obtain quantitative results, a post-SCF method is needed to estimate the complete correlation energy. One such method is multiconfiguration pair-density functional theory (PDFT), which calculates the energy based on the density and on-top pair density obtained from a multiconfiguration wave function. In this work we introduce localized-active-space pair-density functional theory, which uses a LAS wave function for subsequent PDFT calculations. The method is tested for computing spin-state energy gaps in conjugated organic molecules and bimetallic compounds and is shown to give results within 0.05 eV of the corresponding CAS-PDFT results at a significantly lower cost.

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Efficient algorithm for multiconfiguration pair-density functional theory with application to the heterolytic dissociation energy of ferrocene

Cited by 37 publications

References 64 publications

OpenMolcas: From Source Code to Insight

OpenMolcas: From Source Code to Insight

Localized Active Space Pair-Density Functional Theory

Localized Active Space Pair-Density Functional Theory

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