Thermochemistry of HgCH3 and HgCH3+ and the ionization energy of HgCH3

High-level ab initio calculations are performed on HgCH3 and HgCH3+. For HgCH3+, the obtained geometry and vibrational frequencies could be compared to Raman studies of HgCH3+ interacting with biomolecules. HgCH3 was found to be a weakly bound species with a binding energy, D0, of only 3 kcal mol−1. The first adiabatic ionization energy was calculated to be 7.3 ± 0.1 eV, corresponding to an (a1)−1 ionization. The heats of formation were deduced for both the neutral and cation at 298 K, giving values of ΔHf=45±2 and 235 ± 2 kcal mol−1, respectively.