Theoretical study on the electronic states of formylcarbene (HC.CHO) and triplet ketene (H2CCO) and the ultraviolet absorption spectra attributable to these molecules

The adiabatic energies, vibrational frequencies, and geometries of the ground and excited electronic states of formylcarbene and the triplet electronic states of ketene are calculated employing the state-of-the art ab initio methods. With the help of these calculations, certain ultraviolet (UV) absorption bands observed in the flash photolysis of oxazole and iso-oxazole are assigned to formylcarbene and triplet ketene.