Time-dependent optimized coupled-cluster method for multielectron dynamics. III. A second-order many-body perturbation approximation

Pathak, Himadri; Sato, Takeshi; Ishikawa, Kenichi L.

doi:10.1063/5.0008789

Cited by 22 publications

(36 citation statements)

References 67 publications

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“…for general active orbitals (union of hole and particle). It should be noted that, as an orbital-optimised theory, the number of active orbitals is less than the number of the full set of the orbitals {ψ μ } in general [37,41,[46][47][48].…”

Section: Methodsmentioning

confidence: 99%

“…The ground-state MP2 method can be viewed as an approximation to the CCD method considering only those terms which give first-order contributions to the wavefunction with respect to the fluctuation potential [66]. To construct the TD-OMP2 method as a time-dependent, orbital-optimised counterpart of the MP2 method, we begin with the time-dependent CCD Lagrangian, and retain only those terms giving up to second-order contributions to the Lagrangian [48], which reads…”

Section: Review Of Td-omp2 Methodsmentioning

confidence: 99%

“…Recently, to further extend the applicability to heavier atoms and larger molecules interacting with intense laser fields, we have implemented approximate methods within the TD-OCC framework without losing the size-extensivity criteria [47,48]. In Ref.…”

Section: Introductionmentioning

confidence: 99%

“…[47], we introduced a method designated as TD-OCEPA0, which is based on the simplest version of the coupled-electron pair approximation [49]. We have also implemented an approximate method in the TD-OCC framework, based on the many-body perturbation expansion of the coupled-cluster effective Hamiltonian [48]. This method, designated as time-dependent orbital-optimised secondorder many-body perturbation method (TD-OMP2), is a time-dependent extension of the orbital-optimised MP2 method developed by Bozkaya et al [49] for the stationary electronic structure calculations.…”

Section: Introductionmentioning

confidence: 99%

“…It is size-extensive, gauge-invariant, and has a lower scaling of the computational cost [O(N 5 ) where N is the number of active orbitals] than the TD-OCC method with double excitations (TD-OCCD) having a scaling of O(N 6 ). For both the TD-OMP2 and TD-OCEPA0 [47,48], one need not solve for de-excitation amplitudes since they are the complex conjugate of the excitation amplitudes, which further leads to a significant reduction in the computational cost.…”

Section: Introductionmentioning

confidence: 99%

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Study of laser-driven multielectron dynamics of Ne atom using time-dependent optimised second-order many-body perturbation theory

2020

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We calculate the high-harmonic generation (HHG) spectra, strong-field ionisation, and timedependent dipole-moment of Ne using explicitly time-dependent optimised second-order manybody perturbation method (TD-OMP2) where both orbitals and amplitudes are time-dependent. We consider near-infrared (800 nm) and mid-infrared (1200 nm) laser pulses with very high intensities (5 × 10 14 , 8 × 10 14 , and 1 × 10 15 W/cm 2), required for strong-field experiments with the high-ionisation potential (21.6 eV) atom. We compare the result of the TD-OMP2 method with the time-dependent complete-active-space self-consistent field method and the time-dependent Hartree-Fock method. Further, we report the implementation of the TD-CC2 method within the chosen active space, which is also a second-order approximation to the TD-CCSD method, and present results of time-dependent dipole-moment and HHG spectra with an intensity of 5 × 10 13 W/cm 2 at a wavelength of 800 nm. It is found that the TD-CC2 method is not stable in the case with a higher laser intensity, and it does not provide a gauge-invariant description of the physical properties, which makes TD-OMP2 a superior choice to reach out to larger chemical systems, especially for the study of strong-field dynamics. The obtained results indicate that the TD-OMP2 method shows moderate performance, overestimating the response of Ne, while TDHF underestimates it..

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Section: Methodsmentioning

confidence: 99%

Section: Review Of Td-omp2 Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of laser-driven multielectron dynamics of Ne atom using time-dependent optimised second-order many-body perturbation theory

2020

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Time‐dependent coupled‐cluster theory

Ofstad

Aurbakken

Schøyen

et al. 2023

WIREs Comput Mol Sci

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Recent years have witnessed an increasing interest in time‐dependent coupled‐cluster (TDCC) theory for simulating laser‐driven electronic dynamics in atoms and molecules, and for simulating molecular vibrational dynamics. Starting from the time‐dependent bivariational principle, we review different flavors of single‐reference TDCC theory with either orthonormal static, orthonormal time‐dependent, or biorthonormal time‐dependent spin orbitals. The time‐dependent extension of equation‐of‐motion coupled‐cluster theory is also discussed, along with the applications of TDCC methods to the calculation of linear absorption spectra, linear and low‐order nonlinear response functions, highly nonlinear high harmonic generation spectra and ionization dynamics. In addition, the role of TDCC theory in finite‐temperature many‐body quantum mechanics is briefly described along with a few other application areas.This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods Theoretical and Physical Chemistry > Spectroscopy Software > Simulation Methods

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Interpretation of Coupled-Cluster Many-Electron Dynamics in Terms of Stationary States

Pedersen

Kristiansen

Bodenstein

et al. 2020

J. Chem. Theory Comput.

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We demonstrate theoretically and numerically that laser-driven many-electron dynamics, as described by bivariational time-dependent coupled-cluster (CC) theory, may be analyzed in terms of stationary-state populations. Projectors heuristically defined from linear response theory and equation-of-motion CC theory are proposed for the calculation of stationary-state populations during interaction with laser pulses or other external forces, and conservation laws of the populations are discussed. Numerical tests of the proposed projectors, involving both linear and nonlinear optical processes for He and Be atoms and for LiH, CH+, and LiF molecules show that the laser-driven evolution of the stationary-state populations at the coupled-cluster singles-and-doubles (CCSD) level is very close to that obtained by full configuration interaction (FCI) theory, provided that all stationary states actively participating in the dynamics are sufficiently well approximated. When double-excited states are important for the dynamics, the quality of the CCSD results deteriorates. Observing that populations computed from the linear response projector may show spurious small-amplitude, high-frequency oscillations, the equation-of-motion projector emerges as the most promising approach to stationary-state populations.

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Time-dependent optimized coupled-cluster method for multielectron dynamics. III. A second-order many-body perturbation approximation

Cited by 22 publications

References 67 publications

Study of laser-driven multielectron dynamics of Ne atom using time-dependent optimised second-order many-body perturbation theory

Study of laser-driven multielectron dynamics of Ne atom using time-dependent optimised second-order many-body perturbation theory

Time‐dependent coupled‐cluster theory

Interpretation of Coupled-Cluster Many-Electron Dynamics in Terms of Stationary States

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