Associative ionization and dissociative recombination in mercury vapor

We report absolute cross sections for Hg(63P1)+Hg(63P0) associative ionization and Hg+2Hg+2+ e− dissociative recombination in mercury vapor, following saturation of the 253.7-nm transition using pulsed laser excitation. The quantitative time dependencies of all relevant species were determined by combining this information with measurements of the total Hg(63P1) density and the total electron current following the laser pulse. The electron temperature associated with our measurement of kDR is 298 K. The measured values of kAIkAI= (2.5 ± 0.6) × 10−8 cm3 s−1 and kDR = (4.4 ± 1.1) × 10−6cm3 s−1 are 3.5 times smaller and 10.5 times larger, respectively, than those previously reported in cw and discharge flow studies.