Theoretical Study on the Mechanism and Kinetic of the Reactions between Elemental Mercury and Oxidizing Radicals

Due to its fundamental importance, the mechanism and kinetic of the reactions between Hg⁰ and OH/OOH/O₃/NO₃ radicals were investigated in detail by employing quantum chemical calculation. The microcosmic reaction process was calculated and discussed in detail by the UMP2/SDD method, and the activation energies were calculated by the QCISD(T)/SDD method. The kinetic parameters were also calculated by the transition state theory. Theoretical results showed that the calculated activation energies of the Hg+OH, Hg+OOH, Hg+O₃ and Hg+NO₃ reaction were 3.16kcal/mol, 8.32kcal/mol, 12.74kcal/mol and 5.48kcal/mol respectively and the sequence of the calculated rate constants of the four reactions was that: Hg+OH>; Hg+NO₃>;Hg+OOH>;Hg+O₃, which indicated that the sequence of oxidizing ability of the four radicals was that: OH>;NO₃>;OOH>;O₃.