Geminal model chemistry II. Perturbative corrections

Rassolov, Vitaly A.; Xu, Feng; Garashchuk, Sophya

doi:10.1063/1.1738110

Cited by 70 publications

(49 citation statements)

References 50 publications

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“…Many multireference perturbative schemes have been developed in the past, some specifically with geminal product wavefunctions in mind. [13,14,15,16,17,18] A very appealing approach is the multiconfiguration perturbation theory (MCPT) using a nondiagonal zeroth-order HamiltonianĤ 0 , recently proposed by Kobayashi et al [19] Its deficiencies,…”

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confidence: 99%

Simple and inexpensive perturbative correction schemes for antisymmetric products of nonorthogonal geminals

Limacher

Ayers

Johnson

et al. 2014

Phys. Chem. Chem. Phys.

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A new multireference perturbation approach has been developed for the recently proposed AP1roG scheme, a computationally facile parametrization of an antisymmetric product of nonorthogonal geminals. This perturbation theory of second-order closely follows the biorthogonal treatment from multiconfiguration perturbation theory as introduced by Surjan et al., but makes use of the additional feature of AP1roG that the expansion coefficients within the space of closed-shell determinants are essentially correct already, which further increases the predictive power of the method. Building upon the ability of AP1roG to model static correlation, the perturbation correction accounts for dynamical electron correlation, leading to absolute energies close to full configuration interaction results. Potential surfaces for multiple bond dissociation in H2O and N-2 are predicted with high accuracy up to bond breaking. The computational cost of the method is the same as that of conventional single-reference MP2

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confidence: 99%

Simple and inexpensive perturbative correction schemes for antisymmetric products of nonorthogonal geminals

Limacher

Ayers

Johnson

et al. 2014

Phys. Chem. Chem. Phys.

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“…[16], the time evolution of the ground state in the Bohmian formulation implies a cancellation of classical and quantum forces, which show significant nonlinearity for this system. In order to describe it for the duration of five oscillation periods, we use the LQF optimized on L ϭ 3 and L ϭ 5 domains for the "ground state" wavefunction (x 0 ϭ 1.43) and on L ϭ 3 and L ϭ 8 domains for the displaced Gaussian wavepacket (x 0 ϭ 1.63).…”

Section: Examples and Discussionmentioning

confidence: 94%

“…Formally, the AQP defined in this way provides an accurate description if the density is Gaussian on each subspace. Therefore, we generalize our criterion (16) to account for the non-Gaussian shape (or the nonlinear force) by summing over the domains…”

Section: Bohmian Dynamics With the Linearized Quantum Force On Multipmentioning

confidence: 99%

Applicability criterion for semiclassical Bohmian dynamics

Garashchuk

Rassolov

2004

Int J of Quantum Chemistry

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ABSTRACT:In this paper we develop a criterion of the applicability for the trajectory-based semiclassical propagation methods that are exact for Gaussian wavepackets in locally quadratic potentials. The error estimate takes into account a deviation of the wavefunction from the Gaussian form due to the anharmonicity of a potential. The derivation is based on the time-dependent noncoherent solutions of the Schrö dinger equation for a general quadratic potential that form a complete orthonormal time-dependent basis. The anharmonicity is treated as a time-dependent cubic perturbation, which is further related to the nonlinearity of a force acting on trajectories. The criterion is expressed in terms of scalar products of the average force, its first moments, and dispersion of the wavefunction and is efficient in the context of dynamics with the Bohmian trajectories. We give an application for the Bohmian dynamics with the approximate quantum potential, for the Gaussian wavepacket dynamics and for the semiclassical initial value representation propagator.

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“…The present renaissance of geminal theories [29][30][31][32][33][34][35][36][37][38][39][40][41][42] is perhaps a consequence of the need of simple but flexible and qualitatively correct reference states in multi-configuration theory.…”

Section: Introductionmentioning

confidence: 99%