On the method of eigenvalues determination of the “truncated” matrix with morse hamiltonian as an example

A method of precise eigenvalues determination is developed on the basis of high order perturbation theory and applied to di-atomic molecule, as an example. The proposed method makes it possible not only to obtain energy values, but also to estimate a prediction accuracy and limits of its applicability for a specific implemented model. Numerical calculations are performed with the use of the extended Morse oscillator functions. The sixth power of the Morse coordinate is included into the potential function expansion. Analysis of possibility to make calculation in the model of the "truncated" matrix of the Hamiltonian is performed. The comparative possibilities of the method are analyzed with respect to other approaches of the potential functions determination for polyatomic molecules.