The photochemical dynamics of Br2trapped in a Xe matrix have been investigated. Following excitation into either theBthinsp;3Pgr;(0+u) or1Pgr;(1u) states, emission occurs in the far red and infrared region. Analysis of the emission allows the emitting states to be characterized asBthinsp;3Pgr;(0+u)vprime; = 0rarr;Xthinsp;1Sgr;+g, and (tentatively) theAprime;thinsp;3Pgr;(2u)rarr;X1Sgr;+g. The spectrum of theBrarr;Xemission was recorded and exhibited unusually broad vibronic emission lines when compared with Ar spectra. TheBrarr;Xemission lifetime was measured to be 3.6plusmn;0.5 mgr;s and is in excellent agreement with the expected value for the radiative lifetime. The risetime of theBsignal was found to be limited by the detection system (sim;15 ns). The tentatively identifiedAprime;rarr;Xemission has a lifetime of 4plusmn;1 ms. TheA3Pgr;(1u)rarr;Xthinsp;1Sgr;+gemission resolved clearly in Ar and Kr matrices is altogether absent from Br2isolated in Xe. Experiements were performed to measure the relative intensities of theB/Aprime; emissions in Xe and compare them with earlier results from Ar matrices. The XeB/Aprime; ratio was found to be nearly 100 times greater in Xe then in Ar. The observations were found to be independent of temperature from 12 to 60 K and independent of concentrations from 1:500 to 1:10 000, Br2in Xe.
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