Collision-induced IR absorption in gas phase Hg(6 3P1)+HgBr2(1 1Σ+g) reactions: Enhancement of the HgBr(B 2Σ+) product channel

Abstract

We have investigated laser-assisted reactions in Hg/HgBr2 gas mixtures by measuring fluorescence from the product, HgBr radical, following simultaneous IR (1064 nm) and UV (253.7 nm) laser excitation. The product emission has one-photon dependence on both IR and UV laser power, and the results indicate that the excited HgBr product channel is accessed through single photon absorptions by the {Hg–HgBr2} complex. This constitutes the first experimental evidence for an electronically excited state of the {Hg–HgBr2} collision complex, having an energy level >4.9 eV but <6.1 eV. With the addition of tunable IR lasers this technique could provide an important spectroscopic method for investigation of the homologous series of collision complexes, {Hg–HgX2} where (X=F, Cl, Br, I).