Charge transfer of atomic and molecular rare-gas ions with mercury atoms at thermal energy

A drift tube–mass spectrometer apparatus has been used to determine thermal-energy rate coefficients for reactions of the type R++Hg→R+Hg+ and R2++Hg→2R+Hg+, where R denotes an atom of one of the rare gases. Except for He+ ions, charge transfer between atomic rare-gas ions and mercury was found to be immeasurably slow. Both He2+ and Xe2+ exhibited fast charge transfer with mercury; a moderately slow reaction also occurred in the case of Ne2+ ions. Formation of mercury dimer and trimer ions was observed to be quite efficient in xenon–mercury mixtures; rate coefficients for the reaction sequence Hg+→XeHg+→Hg2+→XeHg2+→Hg3+ were estimated to be on the order of 10−31 cm6/sec for the association steps 1 and 3, and about 10−10 cm3/sec for the two-body switching steps 2 and 4.