Deperturbation analysis of the interacting C2Π1/2 (v=5), and D2Σ+ (v=1) levels of ScO

Abstract

Perturbations have been observed between the C2Πi ∼ D2Σ+ pair of interacting states of ScO molecule in the 28,000−30,060 cm-1 region using jet-cooled laser-induced fluorescence spectroscopy at 0.04 cm-1 resolution. The interactions among the D2Σ+, v = 1 and C2Πi, v = 5 states are manifested in irregularity in rotational constants, dispersed fluorescence spectra and relevant Franck-Condon overlaps. The perturbations among these states are understood in terms of homogeneous spin-orbit, spin-electronic and heterogeneous L-uncoupling interactions between the C2Πi ∼ D2Σ+ states. The deperturbed molecular constants of the C2Πi, v = 5 and D2Σ+, v = 1 states have been determined by fitting the observed rovibronic transition wavenumbers to these excited states from the X2Σ+ ground state. The deperturbed position of the D2Σ+, v = 1 state lies only 1.5 cm-1 above the C2Π1/2, v = 5 component and the states interact severely, being pushed apart by 18 cm-1. In addition, the D2Σ+ state is observed in the v = 2 − 4 vibrational levels, which are found to be unperturbed. The deperturbed molecular constants of the vibrational levels of the C2Πi, and D2Σ+ states found in the present and our earlier reported work are used to generate Rydberg-Klein-Rees (RKR) potential curves. Subsequently, the vibrational overlap 〈vΠ|vΣ〉, and radial integrals BvΠ,vΣ, between the C2Πi and D2Σ+ states are computed and used to determine the pure electronic matrix elements connecting the electronic wavefunctions of these states.