Calculations of vibrational energy levels by using a hybrid ab initio and DFT quartic force field: Application to acetonitrile

Didier Bégué (1) , Philippe Carbonnière (1) , Claude Pouchan (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

A hybrid quartic force field with quadratic force constants calculated at the CCSD(T)/cc-pVTZ level and cubic and quartic terms determined by a B3LYP/cc-pVTZ treatment is proposed to compute the vibrational energy levels of acetonitrile from a variational method. Fundamentals and overtones calculated in the range of 300-3200 cm-1 are in fair agreement with the 31 observed data, with an absolute mean deviation of less than 0.8%. These results allow us to explain several Fermi resonances. © 2005 American Chemical Society.

Domaines: Chimie théorique et/ou physique

Didier Bégué, Philippe Carbonnière, Claude Pouchan. Calculations of vibrational energy levels by using a hybrid ab initio and DFT quartic force field: Application to acetonitrile. Journal of Physical Chemistry A, 2005, 109 (20), pp.4611-4616. ⟨10.1021/jp0406114⟩. ⟨hal-01598737⟩