The fluorescence excitation spectra of the NH2Atilde;thinsp;2A1larr;Xtilde;thinsp;2B1transition have been measured in the supersonic free jet. The rotational cooling of the ground state NH2radical results in the observation of only the Pgr; vibronic subbands in the excitation spectra. The fluorescence lifetimes are obtained for single rovibronic levels of theAtilde;thinsp;2A1state in the jet. The radiative lifetime is shortened from 10.3 mgr;s for Pgr;(0,8,0) 11,0to 4.4 mgr;s for Pgr;(0, 14, 0) 11,0with decreasing the excitation wavelength, which is explained by the cubic transition energy dependence of the Einstein A coefficient. Little difference is observed between the lifetimes of the spin components belonging to the same rotational level and between those of the Fermi resonance pairs. The transition moment of theAtilde;thinsp;2A1ndash;Xtilde;thinsp;2B1transition is experimentally determined to be 0.037plusmn;0.004e2agr;20.
展开▼
