Radiative lifetime measurement of vibronic levels of the B2Σz+ state of CaH by laser excitation spectroscopy

The spectrum of the B2Σ → X2Σ transition of gaseous CaH appears in the orange wavelength region with the dominating band heads of the P1 and P2 branches belonging to the (0,0) band at 6328 and 6389 Å. A time-resolved experiment has been performed on several vibrational levels of the low lying B Σ+ state of CaH using laser excitation spectroscopy. Theoretical studies of this molecule are compared with the results of this experiment. The following lifetimes were determined for the B2Σ+ state of the CaH molecule: τν′=0 = 58.1 ± 1.9 ns, τν′=1 = 58.4 ± 2.2 ns and τν′= 2 = 58.5 ± 2.6 ns. The corresponding absorption oscillator strengths are calculated to be f0,0 = 0.105 ± 0.004,f1,1 = 0.104 ± 0.005 and f2,2 = 0.104 ± 0.005.