The reaction of electronically excited state Brast; (4p4, 5s) atoms with Br2and BrI produces electronically excited Brast;2, which gives a complex emission system in the 190ndash;350hyphen;nm region. In both cases the excitation reaction probably involves bromine atom transfer with formation of Brast;2. Similar reactions may be expected between other excitednp4(n+1)shalogen atoms and suitable halogen donor molecules. These experiments were done in a flowinghyphen;afterglow apparatus at 1ndash;8 Torr; the Brast; atoms were generated from interaction of the precursor molecules with metastable argon atoms or with metastable helium atoms. Under highhyphen;pressure excitation conditions, formation of Brast;2by reaction of Brast; with Br2followed by vibrational relaxation may contribute to the excitation mechanism for the Brast;2laser system initiated byehyphen;beam or discharge pumping of Br2/Ar mixtures.
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