Strong 5 mgr;m CO laser emission was observed in the flash photolysis (lgr;ge; 165 nm) of mixtures of O2and CHBr3in the presence of large amounts of diluent (SF6, Ar, or He). About 60 vibrationhyphen;rotation transitions were identified in the range between Dgr;ngr; equals; 14rarr;13 and 2rarr;1. The laser intensity was found to vary linearly with flash energy. The effects of various additives (He, Ar, SF6, CO, N2, N2O, and CO2) were investigated. The stimulated emission is concluded to result primarily from the fourhyphen;centered reactionCHplus;O2rarr;1COdagger;plus;OHdagger;,Dgr; H10equals;minus;159thinsp;kcalsol;mole.Other possible minor reactions were also considered. No OH emission was detected under the same experimental conditions. With the aid of a bandhyphen;pass filter (8.6ndash;15 mgr;m range), 10 mgr;m CO2emission was observed concurrently with the 5 mgr;m CO emission. The CO2emission, which consisted of theP(58)ndash;(70) lines of the (001)rarr;(020) band, was found to vary strongly with the partial pressure of O2. Since both the intensity of this emission and the yield of CO2increased linearly with flash energy, the (001) rarr; (020) CO2emission is believed to be the direct consequence of the following CHplus;O2reaction:CHplus;O2rarr;10Hplus;CO2dagger;,Dgr; H100equals;minus;184thinsp;kcalsol;mole.This is the first example of lasing from a chemically produced excited polyatomic molecule. When a small amount of N2O or CO2was added to the O2sngbnd;CHBr3sngbnd;He mixture, the regular (001)rarr;(100) band of both molecules began to lase at sim;P(18)ndash;P(28), presumably resulting from the energy transfer process OHdagger;plus;M(000)rarr;OHplus;M(001), where M equals; CO2or N2O.
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