Accurate ab initio prediction of the rovibrational energy levels and equilibrium geometry of carbonyl selenide (OCSe)

The geometry and the anharmonic force field of carbonyl selenide (OCSe) hav e been investigated using multi reference configuration interaction theory. The computed potential energy surface and geometry have been refined by a least squares adjustment of the theoretical spectroscopic parameters to rep roduce all available spectroscopic frequencies and constants. The Fermi int eraction between the 2 nu(2) and nu(3) bands has been investigated in detai l using perturbative and variational methods.