Simultaneous analysis of rotational and vibrational–rotational spectra of DF and HF to obtain irreducible molecular constants for HF

Abstract

Analytic expressions of corrections for the breakdown of the Born−Oppenheimer approximation to Dunham's Y ij with optimal parameters, i.e., determinable clusters of expansion coefficients, are applied to a data analysis of the rotational and vibrational-rotational transitions of HF reported in the literature. All the available spectral lines of the two isotopologues, DF and HF, are simultaneously fitted to a single set of molecular parameters of HF within experimental errors. Fitting of a data set of 595 spectral transitions for DF and HF has generated only 20 minimal independent parameter values, i.e., "irreducible" molecular constants of HF, that are sufficient to precisely generate 82 Y ij coefficients and 144 band constants in total: 41 Y ij and 72 band constants each for DF and HF.

Vibrational–rotational spectra of 13CS and global multi-isotopologue analysis

“…[19]; additional details of the analysis are provided in Ref. [20]. The spectral uncertainties, d obs , were those specified in each paper.…”

“…The Dunham-like treatment of the Schrödinger equation of the Hamiltonian (1) generates analytical expressions for the vibrational-rotational term values [19,20,22], which enable an analysis of a spectral data set of CS with a single set of Born-Oppenheimer fitting parameters, U x (=l 1 Tables 1 and 2 of Ref. [20], respectively.…”

“…As our measured vibrational-rotational wavenumbers for 12 C 32 S are slightly more accurate than those of Ram et al [17], both sets of values were included in the data set that was subjected to a global multi-isotopologue spectral analysis. The global analysis employed here, which was comprehensively reviewed [18], is based on a non-Born-Oppenheimer effective Hamiltonian expressed with determinable molecular parameters in a set [19][20][21] as follows:…”