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arXiv · 0909.3417

Ab initio potential energy surfaces for NH-NH with analytical long range

Liesbeth M. C. Janssen·Gerrit C. Groenenboom·Ad van der Avoird·Piotr S. Żuchowski·Rafal Podeszwa
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Abstract

We present four-dimensional ab initio potential energy surfaces for the three spin states of the NH-NH complex. The potentials are partially based on the work of Dhont et al. [J. Chem. Phys. 123, 184302 (2005)]. The surface for the quintet state is obtained at the RCCSD(T)/aug-cc-pVTZ level of theory and the energy diferences with the singlet and triplet states are calculated at the CASPTn/aug-cc-pVTZ (n = 2; 3) level of theory. The ab initio potentials are fitted to coupled spherical harmonics in the angular coordinates, and the long range is further expanded as a power series in 1/R. The RCCSD(T) potential is corrected for a size-consistency error prior to fitting. The long-range coeficients obtained from the fit are found to be in good agreement with perturbation theory calculations.

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Liesbeth M. C. Janssen, Gerrit C. Groenenboom, Ad van der Avoird, Piotr S. Żuchowski, Rafal Podeszwa. 2009-09-18. Ab initio potential energy surfaces for NH-NH with analytical long range. https://doi.org/10.1063/1.3268920

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