The geometry and the inversion potential function of formaldehyde in the Ã^{1}A _{2} and ã^{3}A _{2} electronic states
Abstract
The formaldehyde molecule (H _{2}CO) is nonplanar in the excited Ã^{1}A _{2} and ã^{3}A _{2} electronic states. We have developed the "semirigid invertor" Hamiltonian to calculate the rotationinversion energy levels of such a molecule, and used leastsquares fitting to determine the inversion potential function and geometrical parameters from the data for H _{2}CO and D _{2}CO in both these states. In the model the bond lengths and HCH angle are allowed to vary as the molecule inverts and this semirigid flexibility improves the fit. We confirm previous experimental findings that the barrier to inversion in the triplet state is more than twice that of the singlet state; these results do not accord with ab initio calculations.
 Publication:

Journal of Molecular Spectroscopy
 Pub Date:
 July 1982
 DOI:
 10.1016/00222852(82)902983
 Bibcode:
 1982JMoSp..94..114J