Izvestiya of Saratov University.
Physics
ISSN 1817-3020 (Print)
ISSN 2542-193X (Online)

stable algorithm for calculation

Numerical Simulation of Vibronic Spectra for Polyatomic Molecules

Algorithms for vibrational analysis of the excited electronic states of molecules and calculations of molecular structure at electronic excitation are described. Algorithms are realized in the form of special programs. Basic data of programs are described. All initial data for this complex are formed on the basis of the molecular dynamics and quantum models.

Calculation of Atomic Integrals with Exponentialy Correlated Functions

A new type of correlation atomic integrals occurring in variation energy calculations of three-particle Coulomb systems is studied. A integrand in them along with an interparticle distance linear term under an exponent additionally contains a quadratic term. It is demonstrated that these integrals are analytically expressed through Faddeeva function of a pure imaginary argument and its derivatives. A stable and fast algorithm for calculation of Faddeeva function derivatives to the twentieth order is developed.