Evidence of a weak dipole transition moment between the X(1)0g+ and (3)1u(5(3)P1) electronic energy states in Cd2

Abstract

Theoretical and experimental evidence of a weak M(z)(R) dipole transition moment between the X(1)0g+ ground and (3)1u(5(3)P1) excited states in Cd2 is presented. Two independent attempts at recording an excitation spectrum of the (3)1u <-- X(1)0g+ transition using a laser beam crossed with a supersonic free-jet expansion beam are reported. The measurements were performed in a spectral range predicted as a result of both ab initio calculations of the electronic energy-state potentials involved in the transition and a simulation of the excitation spectrum. Unfortunately it was impossible to provide unambiguous experimental support for the calculated (3)1u-state potential, due to the very poor signal to noise ratio. However, the experimental results corroborate the very small values of the <(3)1u|M(z)|X(1)0g+> elements obtained in the calculations. This work provides as a reliable starting point for further analysis of the (3)1u-state characteristics.