Ab initio Cl calculations of the anharmonic force field of methylene-imine CH2NH [Calcul ab initio du champ de force quartique et du spectre vibrationnel anharmonique de la molecule de methylene-imine H2CNH]
Résumé
The ab initio MP2/6-311G** molecular energies gradients and hessians have been evaluated at 370 points for the ground electronic state of H2CNH molecule. The corresponding potential energy surface has been fitted to obtain a cubic and quartic force field from which the fundamental anharmonic frequencies have been determined using perturbational, variational and a variation-perturbation procedures. Theoretical predictions reproduce the experimental to a degree of agreement which allows a complete assignment of all fundamental bands of H2CNH and eight of its isotopomers.