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Journal Articles Journal of Chemical Physics Year : 2016

Adaptive vibrational configuration interaction (A-VCI): a posteriori error estimation to efficiently compute anharmonic IR spectra

Abstract

A new variational algorithm called adaptive vibrational configuration interaction (A-VCI) intended for the resolution of the vibrational Schrödinger equation was developed. The main advantage of this approach is to efficiently reduce the dimension of the active space generated into the configuration interaction (CI) process. Here, we assume that the Hamiltonian writes as a sum of products of operators. This adaptive algorithm was developed with the use of three correlated conditions i.e. a suitable starting space ; a criterion for convergence, and a procedure to expand the approximate space. The velocity of the algorithm was increased with the use of a posteriori error estimator (residue) to select the most relevant direction to increase the space. Two examples have been selected for benchmark. In the case of H 2 CO, we mainly study the performance of A-VCI algorithm: comparison with the variation-perturbation method, choice of the initial space, residual contributions. For CH 3 CN, we compare the A-VCI results with a computed reference spectrum using the same potential energy surface and for an active space reduced by about 90 %.
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Origin : Files produced by the author(s)
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Dates and versions

hal-01310708 , version 1 (03-05-2016)

Identifiers

  • HAL Id : hal-01310708 , version 1

Cite

Romain Garnier, Marc Odunlami, Vincent Le Bris, Didier Bégué, Isabelle Baraille, et al.. Adaptive vibrational configuration interaction (A-VCI): a posteriori error estimation to efficiently compute anharmonic IR spectra. Journal of Chemical Physics, 2016, 144 (20). ⟨hal-01310708⟩

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