Branching ratios, radiative lifetimes, and transition dipole moments for tantalum nitride, TaN

The dispersed laser induced fluorescence resulting from excitation in the regions of the [17.58]0⁺ − X¹Σ⁺ (0, 0), [18.42]0⁺ − X¹Σ⁺ (0, 0), [19.22]1 − X¹Σ⁺ (0, 0), and [19.40]1 − X¹Σ⁺ (0, 0) bands of tantalum nitride, ¹⁸¹TaN, have been recorded and analyzed. The branching ratios and radiative lifetimes for the [17.58]0⁺(v = 0), [18.42]0⁺(v = 0), [19.22]1⁺(v = 0), and [19.40]1(v = 0) states have been determined. From these values the transition dipole moments for visible bands are determined. Vibrational spacing in the X¹Σ⁺ state and the spin-orbit splitting of the a³Δ state are measured and compared with predicted values. The dispersed fluorescence spectra and determined branching ratios reveal that the most effective mechanism for populating the a3Δ₁(J=1,v=0) state, which will be used in future P- and T-violation measurements, is via excitation of the [18.42]0⁺ − X¹Σ⁺ (0, 0) band followed by subsequent spontaneous or stimulated emission.