On an inconsistency between experimental and non-empirical data on the lifetimes of electronic–vibrational–rotational states of the H2, HD, and D2 molecules

Abstract

A comparative analysis is carried out for all published to date experimental and non-empirical data on radiative lifetime of electronic–vibrational–rotational (EVR) levels for the three most common isotopologues of the hydrogen molecule. It is found that 792 available experimental values are extremely fragmentary. The majority of EVR levels have been studied only in one work. The available data give no clear notion about dependences of the radiative lifetime on the vibrational and rotational quantum numbers and complicates comparison of the results obtained by means of different methods and/or in different works. Comparison with non-empirical results is hampered by the absence of computational results for 24, 30, and 90% experimentally studied EVR levels of H2, D2, and HD, respectively. It is shown that, for a significant number EVR levels (46, 68, and 80%, respectively, for H2, D2, and HD), which have been studied both experimentally and theoretically, there is a direct contradiction between experimental and computational results on the radiative lifetime. More accurate and independent experimental measurements of the radiative lifetimes and more accurate non-empirical calculations with the use of nonadiabatic models are needed to resolve the revealed contradictions.