An efficient procedure for the calculation of the vibrational energy levels of any triatomic molecule

Abstract

It is often desirable to determine the parameters of an analytical representation of a molecular potential energy surface by a least squares fit of the vibrational energy levels to experimental values. The variational method is the only accurate method to obtain these levels, and this paper describes our most efficient procedure for the construction of the hamiltonian matrix. Applications of the procedure to CO₂ and SO₂ are described. Advances made in reducing the size of the variational problem are also discussed.