Electronic Quenching Of The A(1)Sigma(+) State Of Nah

We have measured the rates for quenching of the upsilon=4 and upsilon=5 vibrational levels of the A(1) Sigma(+) state of sodium hydride using helium, argon, and nitrogen as the quenching gas. The measured rates are compared with earlier results for state-to;state quenching rates. The measured rates for quenching by helium and argon are similar, whereas that for quenching by nitrogen is an order of magnitude higher. In addition, at high nitrogen gas pressures the fluorescence was observed to undergo large scale intensity fluctuations. It is suggested that this may be due to a chemical rather than a physical mechanism