The forbidden predissociation of metastable H2(cthinsp;3Pgr;uminus;) molecules studied by state specific lifetime measurements

摘要

Using laser induced fluorescence detection of metastable H2(cthinsp;3Pgr;minus;u,v=0ndash;3,N=1ndash;4) molecules in a beam at different distances from the source, the lifetime of resolved fine structure levels was determined. It was found to be much shorter for theF2levels (sim;150ndash;10 mgr;s forv=0ndash;3, respectively) than for theF1plusF3components (several hundred to 70 mgr;s). This is due to a forbidden (Dgr;Nne;0) predissociation by thebthinsp;3Sgr;+ustate, which operates preferentially on theF2levels. Accurate boundndash;free Franckndash;Condon factor calculations reproduce the increasing trend of the predissociation rate in going fromv=0ndash;3. The absolute predissociation rates from previous theoretical work, however, can only be brought into agreement with the experimental results if they are multiplied with a common scale factor of 38. thinsp;