On the determination of spectroscopic constants as functions of intramolecular parameters

Abstract

The symmetrised form of the operator Van Vleck perturbation theory is considered (the irreducible tensorial set theory is used as the mathematical basis of this consideration). General formulae which define spectroscopic rotational, centrifugal and resonance constants of molecules as functions of reduced matrix elements of vibrational operators are obtained. Algorithms for the ES-1055 computer have been derived on the basis of the formulae obtained, and a system of analytical calculations using the language 'REDUCE' has been created. The dyad and pentad of the CH4-type molecule are considered for illustration. Formulae are obtained which connect spectroscopic and intramolecular constants not only for isolated but also for interacting vibrational states.