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Mashkovtsev D, Orimoto Y, Aoki Y. Fast and Accurate Calculation of the UV-Vis Spectrum with the Modified Local Excitation Approximation. J Chem Theory Comput 2023; 19:5548-5562. [PMID: 37471461 DOI: 10.1021/acs.jctc.3c00266] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
The local excitation approximation (LEA), a method for the calculation of electronic excitations localized in a specific region of a molecule, has been modified with new approaches to enhance the accuracy of the original method. The primary concept behind LEA involves isolating the region of interest as a submolecule from the full molecule using a localization method, followed by calculating electronic excitations solely within this submolecule. In this study, we examined approaches that improve the accuracy in describing the region of interest, particularly its molecular orbital energies. Additionally, the localization method was extended with a new projection technique to accelerate calculations. These approaches were studied in time-dependent density functional theory (TDDFT) calculations applied to four testing systems with a chromophore as the region of interest: two basic linear molecules, acrolein surrounded by 24 water molecules, and a model of a green fluorescent protein. For all studied systems, the results of TDDFT calculations combined with LEA exhibited near-zero error when groups of atoms adjacent to the chromophore were explicitly included in the submolecule. This was achieved with at least a quadratic speedup of the calculation time as a function of the submolecule size.
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Affiliation(s)
- Denis Mashkovtsev
- Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka 816-8580, Japan
| | - Yuuichi Orimoto
- Department of Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka 816-8580, Japan
| | - Yuriko Aoki
- Department of Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka 816-8580, Japan
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2
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Saitow M, Uemura K, Yanai T. A local pair-natural orbital-based complete-active space perturbation theory using orthogonal localized virtual molecular orbitals. J Chem Phys 2022; 157:084101. [DOI: 10.1063/5.0094777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The multireference second-order perturbation theory (CASPT2) is known to deliver a quantitative description of various complex electronic states. Despite its near-size-consistent nature, the applicability of the CASPT2 method to large, real-life systems is mostly hindered by large computational and storage costs for the two-external tensors, such as two-electron integrals, amplitudes, and residuum. To this end, Menezes and co-workers developed a reduced-scaling CASPT2 scheme by incorporating the local pair-natural orbital (PNO) representation of the many-body wave functions using non-orthonormal projected atomic orbitals (PAOs) into the CASPT theory [F. Menezes et al., J. Chem. Phys. 145, 124115 (2016)]. Alternatively, in this paper, we develop a new PNO-based CASPT2 scheme using the orthonormal localized virtual molecular orbitals (LVMOs) and assess its performance and accuracy in comparison with the conventional PAO-based counterpart. Albeit the compactness, the LVMOs were considered to perform somewhat poorly compared to PAOs in the local correlation framework because they caused enormously large orbital domains. In this work, we show that the size of LVMO domains can be rendered comparable to or even smaller than that of PAOs by the use of the differential overlap integrals for domain construction. Optimality of the MOs from the CASSCF treatment is a key to reducing the LVMO domain size for the multireference case. Due to the augmented Hessian-based localization algorithm, an additional computational cost for obtaining the LVMOs is relatively minor. We demonstrate that the LVMO-based PNO-CASPT2 method is routinely applicable to large, real-life molecules such as Menshutkin SN2 reaction in a single-walled carbon nanotube reaction field.
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Affiliation(s)
- Masaaki Saitow
- Department of Chemistry, Graduate School of Science, Nagoya University, Furocho, Chikusa Ward, Nagoya, Aichi 464-8601, Japan
| | - Kazuma Uemura
- Department of Chemistry, Graduate School of Science, Nagoya University, Furocho, Chikusa Ward, Nagoya, Aichi 464-8601, Japan
| | - Takeshi Yanai
- Department of Chemistry, Graduate School of Science, Nagoya University, Furocho, Chikusa Ward, Nagoya, Aichi 464-8601, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furocho, Chikusa Ward, Nagoya, Aichi 464-8601, Japan
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Paul AC, Folkestad SD, Myhre RH, Koch H. Oscillator Strengths in the Framework of Equation of Motion Multilevel CC3. J Chem Theory Comput 2022; 18:5246-5258. [PMID: 35921447 PMCID: PMC9476665 DOI: 10.1021/acs.jctc.2c00164] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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We present an efficient implementation of the equation
of motion
oscillator strengths for the closed-shell multilevel coupled cluster
singles and doubles with perturbative triples method (MLCC3) in the
electronic structure program eT. The orbital space is split into an active part treated with
CC3 and an inactive part computed at the coupled cluster singles and
doubles (CCSD) level of theory. Asymptotically, the CC3 contribution
scales as floating-point operations, where nV is the total number of virtual orbitals while nv and no are the
number of active virtual and occupied orbitals, respectively. The
CC3 contribution, thus, only scales linearly with the full system
size and can become negligible compared to the cost of CCSD. We demonstrate
the capabilities of our implementation by calculating the ultraviolet–visible
spectrum of azobenzene and a core excited state of betaine 30 with
more than 1000 molecular orbitals.
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Affiliation(s)
- Alexander C Paul
- Department of Chemistry, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway
| | - Sarai Dery Folkestad
- Department of Chemistry, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway
| | - Rolf H Myhre
- Department of Chemistry, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway
| | - Henrik Koch
- Department of Chemistry, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway.,Scuola Normale Superiore, Piazza dei Cavaleri 7, 56126 Pisa, Italy
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Wang K, Xie Z, Luo Z, Ma H. Low-Scaling Excited State Calculation Using the Block Interaction Product State. J Phys Chem Lett 2022; 13:462-470. [PMID: 35015548 DOI: 10.1021/acs.jpclett.1c03445] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We develop an automatic and efficient scheme for the accurate construction of the bases for excitonic models, which can enable "black-box" excited state structure calculations for large molecular systems. These new and optimized bases, which are named the block interaction product state (BIPS), can be expressed as the direct products of the local states for each chromophore. Each chromophore's local states are selected by diagonalization of its reduced density matrix, which is obtained by quantum chemical calculation of the small subsystem composed of the chromophore and its nearest neighbors. We implemented the BIPS framework with fragment-based calculations considering two- and three-body interactions. Test calculations for eight different molecular aggregates demonstrate that this framework provides an accurate description of not only the excitation energies but also the first-order wave function properties (dipole moment and transition dipole moment) of the low-lying excited states at a low-scaling computational cost.
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Affiliation(s)
- Ke Wang
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210023, China
| | - Zhaoxuan Xie
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210023, China
| | - Zhen Luo
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210023, China
| | - Haibo Ma
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210023, China
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5
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Abstract
We present a new and efficient implementation of the closed shell coupled cluster singles and doubles with perturbative triples method (CC3) in the electronic structure program eT. Asymptotically, a ground state calculation has an iterative cost of 4nV4nO3 floating point operations (FLOP), where nV and nO are the number of virtual and occupied orbitals, respectively. The Jacobian and transpose Jacobian transformations, required to iteratively solve for excitation energies and transition moments, both require 8nV4nO3 FLOP. We have also implemented equation of motion (EOM) transition moments for CC3. The EOM transition densities require recalculation of triples amplitudes, as nV3nO3 tensors are not stored in memory. This results in a noniterative computational cost of 10nV4nO3 FLOP for the ground state density and 26nV4nO3 FLOP per state for the transition densities. The code is compared to the CC3 implementations in CFOUR, DALTON, and PSI4. We demonstrate the capabilities of our implementation by calculating valence and core excited states of l-proline.
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Affiliation(s)
- Alexander
C. Paul
- Department
of Chemistry, Norwegian University of Science
and Technology, NTNU, 7491 Trondheim, Norway
| | - Rolf H. Myhre
- Department
of Chemistry, Norwegian University of Science
and Technology, NTNU, 7491 Trondheim, Norway
| | - Henrik Koch
- Department
of Chemistry, Norwegian University of Science
and Technology, NTNU, 7491 Trondheim, Norway
- Scuola
Normale Superiore, Piazza dei Cavaleri 7, 56126 Pisa, Italy
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