Cavity ring-down laser absorption spectroscopy of the E3Δ-X3Δ transition of VN

Abstract

The (0,0) band of the electronic transition of VN near 450.5 nm has been investigated using the technique of laser vaporization/reaction with free jet expansion and cavity ring-down laser absorption spectroscopy. A new transition system was observed, which has been assigned as the E 3Δ-X 3Δ system. All three ΔΩ = 0 subband transitions were recorded and rotationally analyzed. A least-squares fit of the measured line positions yielded molecular constants for the new E 3Δ state. The bond length, r o, of the E 3Δ state was determined to be 1.6937 Å, which is the longest among the known states of VN. The E 3Δ state is expected to arise from the electronic configuration 1δ 110σ 1, where the 10σ orbital is an antibonding orbital. A comparison of the observed electronic states of VN to those of the isoelectronic TiO molecule supports the assignment.