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>The temperature dependence of rsquo;rsquo;single collisionrsquo;rsquo; bimolecular beamndash;gas chemiluminescent reactions. II. Experimental studies
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The temperature dependence of rsquo;rsquo;single collisionrsquo;rsquo; bimolecular beamndash;gas chemiluminescent reactions. II. Experimental studies
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机译：The temperature dependence of rsquo;rsquo;single collisionrsquo;rsquo; bimolecular beamndash;gas chemiluminescent reactions. II. Experimental studies
We consider rsquo;rsquo;single collisionrsquo;rsquo; bimolecular beamndash;gas chemiluminescent reactions in which a metal beam formed effusively intersects a tenuous atmosphere of oxidant gas (10minus;4ndash;10minus;6torr) resulting in the emission of visible radiation from excited electronic states of the reaction products. From recently derived relationships which allow the determination of the temperature dependence for the observed chemiluminescence we deduce upper bounds for Dgr;Hvaporization (Dgr;Hsub). In addition, for systems in which Dgr;His accurately known through independent studiesEexpmay be evaluated. Derived relationships are demonstrated experimentally through studies of ten bimolecular reactions. We consider the reaction of strontium atoms and fluorine molecules. Here, reaction occurs with one internal state of the metal atom (ground1S0states). Dgr;Hsub(Sr),Eexp(SrF,C2Pgr;), andEexp(SrF,D2Sgr;+) are determined by monitoring the chemiluminescence from the SrFC2Pgr; andD2Sgr;+excited electronic product states. By combining the determined activation energies with reasonable estimates of relative frequency factors for theC2Pgr; andD2Sgr;+states we deduce that theD2Sgr;+state of SrF is long lived (metastable). Results are also presented for the reactions of Sc, Y, and La with O2, NO2, and N2O. Here the metal beams are characterized by a substantial internal state population. The effect of the internal state population characterizing the metal beams is analyzed. We deduce an upper bound for Dgr;Hvap(Sc, Y, La) from the nine reactions studied.Eexpfor formation in thevprime;=0 level of the ScO and YO A2Pgr; states, and thevprime;=0 level of the LaO C2Pgr; state, is deduced for the three possible oxidations with O2, NO2, and N2O. The resultant experimentally determined activation energies are compared with those expected on the basis of mechanistic models used to describe the oxidation reactions of Group IIIB atoms.
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