Theoretical investigation of the photoelectron spectra of the vinylidene anions

The vibrational structures of the first photoelectron bands of the vinylide ne anion and its deuterated isotopomers have been calculated theoretically, by an ab initio quantum dynamical method. Very good agreement with the exp erimental results of Lineberger and coworkers has been obtained. This impli es a reproduction of the relevant vibrational frequencies to within 20-30 c m(-1) for all three neutral isotopomers. By a slight change of the anionic C-C bond length the agreement on the spectral intensities can be further im proved. In this way an accurate estimate of the equilibrium geometry of the vinylidene anion has also been deduced.