Intramolecular dynamics of small molecules ‐ empirical evaluation of adiabatic and nonadiabatic corrections

Abstract

AbstractFrom published analyses of vibration‐rotational spectra of diatomic and linear triatomic molecules, we evaluated the term coefficients Ykl, and various Zkl in terms of mechanical (related to vibration and rotation of the nuclei about the centre of mass), adiabatic, and nonadiabatic vibrational and rotational effects (as the associated electrons follow imperfectly the nuclei). We propose generalisations about relative orders of magnitudes of mechanical, adiabatic and nonadiabatic effects that pertain to intramolecular dynamics of free small molecules, and discuss the importance of taking into account all these effects in either comparing results deduced from experiment with those drawn from computations of molecular electronic structure or deducing structural information from spectral parameters.