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DOE OSTI · 22255117

Multi-reference vibration correlation methods

Pfeiffer, Florian·Rauhut, Guntram
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Abstract

State-specific vibration correlation methods beyond the vibrational multi-configuration self-consistent field (VMCSCF) approximation have been developed, which allow for the accurate calculation of state energies for systems suffering from strong anharmonic resonances. Both variational multi-reference configuration interaction approaches and an implementation of approximate 2nd order vibrational multi-reference perturbation theory are presented. The variational approach can be significantly accelerated by a configuration selection scheme, which leads to negligible deviations in the final results. Relaxation effects due to the partitioning of the correlation space and the performance of a VMCSCF modal basis in contrast to a standard modal basis obtained from vibrational self-consistent field theory have been investigated in detail. Benchmark calculations based on high-level potentials are provided for the propargyl cation and cis-diazene.

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74 ATOMIC AND MOLECULAR PHYSICSCATIONSPARTITIONPERTURBATION THEORYRELAXATIONSELF-CONSISTENT FIELD

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Pfeiffer, Florian, Rauhut, Guntram. 2014-02-14. Multi-reference vibration correlation methods. https://doi.org/10.1063/1.4865098

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