Variational calculation of energies of highly excited rovibrational states of 12C16O2

Accurate variational calculations of energies of highly excited rovibrational states of (CO2)-C-12-O-16 using a Lanczos recursion are presented. In a first step, we use experimental rovibrational transition frequencies to determine by a least-square fitting procedure a potential energy surface for the CO2 molecule. This potential energy surface is expressed as a multidimensional power series expansion in the normal coordinates. It is then used to determine all the rovibrational energies for symmetry e levels up to a rotational number J = 200, a vibrational energy of 13 000 cm(-1), and a vibrational angular momentum l = 13. (C) 2002 Elsevier Science (USA).