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

Abstract The dispersed laser induced fluorescence resulting from excitation in the regions of the [17.58]0 +  −  X 1 Σ + (0, 0), [18.42]0 +  −  X 1 Σ + (0, 0), [19.22]1 −  X 1 Σ + (0, 0), and [19.40]1 −  X 1 Σ + (0, 0) bands of tantalum nitride, 181 TaN, 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 X 1 Σ + state and the spin-orbit splitting of the a 3 Δ 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 a 3 Δ 1 ( J = 1 , v = 0 ) state, which will be used in future P - and T -violation measurements, is via excitation of the [18.42]0 +  −  X 1 Σ + (0, 0) band followed by subsequent spontaneous or stimulated emission.