Analysis of singlet and triplet systems of yttrium hydride, YH and YD

Abstract

Six new electronic band systems, ascribed to YH, have been observed in emission in the negative glow of a 'composite wall' hollow cathode lamp. Five of the similar systems of YD have also been observed. They appear between 4500 and 9000 Å. The vibrational analysis and observation of the related isotope effect permitted us to distinguish and partially classify these systems. Rotational analysis made it possible to identify the corresponding transitions as 3Φ → 3Δ, (1Π, 1Σ) → 1Σ, and (1Σ, 1Δ) → 1Π.Rotational constants of the ν = 0 states are given in this paper. Moreover, equilibrium molecular constants derived from the rotational study of a number of bands, namely (0, 0) and (1, 1) of YH and (1, 0), (2, 1), (3, 2), (0, 0), (1, 1), (2, 2), and (0, 1) of YD, are given for the states of the 1Σ → 1Σ transition. Franck–Condon factors of this system are estimated.