The Electronic Transition Moment Function for the B3Π–X3Δ System of TiO

Abstract

Several vibronic bands associated with v′=0, 1, and 2 for the B3Π–X3Δ transition of TiO have been observed using a dispersed laser induced fluorescence (DLIF) technique. From intensity distributions of the DLIF spectra, the dependence of the electronic transition moment Re(r) for the B3Π–X3Δ system was determined as a function of the internuclear distance r. For the determination of the Re(r) function, a merged fit of the observed distributions, the reported radiative lifetimes of three vibrational levels in the B3Π state, and the reported value of Re(r) for the (0, 0) band were performed; Re(r) was determined as Re(r)=1.3723(79)[1−0.316(81)(r−r0)+2.0(10)(r−r0)2](r0=1.6648 Å and 1.5131 Å≤r≤1.8636 Å). The r-dependence of Re(r) was much smaller than the reported theoretical predictions. The obtained values of Re(r) were analyzed simultaneously with the hyperfine coupling constants for the X3Δ state and the spin–orbit constants for the X3Δ and B3Π states to assess the ionic and orbital characters. It was found that the r-dependence of Re(r) could be accounted for by both the configuration interaction in the B3Π state and the polarization in the unpaired 9σ and 4π orbitals.