Absolute Cross Section for Hg(3P1) + H2 and the Imprisonment Lifetimes for Hg(3P1) at Low Opacity

Abstract

Steady-state hydrogen-atom concentrations produced by the mercury-photosensitized decomposition of molecular hydrogen are detected by Lyman-α photometry. On the basis of the natural lifetime of Hg(3P1) and the mechanism for the reaction, quenching plots are constructed, and the over-all bimolecular rate constant for Hg(3P1) + H2 is calculated. The absolute cross section for Hg(3P1) + H2 is determined to be 10.8 ± 0.4 Å2 in the limit of low mercury opacity. This result agrees with other recent experimental determinations. In addition, experimental values of imprisonment lifetimes for Hg(3P1) as a function of mercury concentration are estimated and are compared with other low-opacity and high-opacity results. The results are also compared to various theoretical predictions of imprisonment lifetimes.