Collisional quenching of Hg₂ (AO⁺_g)

The rate constants for quenching of the metastable AO⁺_g state of Hg₂ in two and three body collisions with background Hg atoms have been measured by a pump-probe, laser-induced fluorescence technique. The Hg₂ (AO⁺_g) species was produced by photoassociating thermal Hg-Hg pairs at 266 nm which populates the D1_u level of Hg₂. Subsequent collisions relax the dimer into the AO⁺_g state. The temporal history of the A state number density was monitored by driving the GO⁺_u ← AO⁺_g transition in the yellow (λ ∼ 564 nm) and observing GO⁺_u → XO⁺_g emission in the ultraviolet (λ ∼ 210-240 nm). The two and three body rate constants for quenching of Hg₂ (AO⁺_g) by Hg were measured to be (4.5 ± 3.0) × 10^-15 cm³·s^-1 and (1.8 ± 0.4) × 10^-33 cm⁶·s^-1, respectively.