Jet-cooled laser-induced fluorescence spectroscopy of B2Σ+-X2Σ+ system of scandium monoxide: Improved molecular constants at equilibrium

The investigation on B2Σ+-X2Σ+ system of ScO was extended to higher vibrational levels by laser-induced fluorescence (LIF) spectroscopy in a free-jet. We have observed rotationally resolved excitation spectra for (4,0), (3,0), (2,0), and (1,2) bands in addition to the previously observed (0,0) and (1,0) bands. The wavenumbers of these bands were fitted to a Hamiltonian matrix to determine the molecular constants for the vibrational levels up to ν′=4 of the B2Σ+ state and ν″=2 of the X2Σ+ state. In addition, the vibration constants of the ground states were determined from the dispersed fluorescence wavenumbers between B2Σ+ (ν′=0-4) and X2Σ+ (ν″=0-8) transitions. The equilibrium molecular constants, derived from the extensive set of molecular constants for individual vibrational levels, were used to construct RKR potential energy curves for both the electronic states. The Franck-Condon factors were also calculated for the B2Σ+-X2Σ+ transition.

► B2Σ+-X2Σ+ system of ScO molecule extended to higher vibrational levels. ► Four new bands viz. (4,0), (3,0), (2,0), and (1,2) observed. ► Vibrational term energy up to ν″=8 levels for X2Σ+ state determined. ► Equilibrium molecular constants for X and B states improved. ► Franck-Condon factors for B2Σ+-X2Σ+ transition calculated.