Theoretical Study of the Monohydration of Mercury Compounds of Atmospheric Interest

Abstract

The structures, vibrational frequencies, and model IR spectra of the monohydrates of oxygenated mercury compounds (BrHgO, BrHgOH, BrHgOOH, BrHgNO 2 , BrHgONO, and HgOH) have been theoretically studied using the ωB97X-D/ aug-cc-pVTZ level of theory. The ground state potential energy surface exhibits several stable structures of these monohydrates. The thermodynamic properties of the hydration reactions have been calculated at different levels of theory including DFT and coupledcluster calculations DK-CCSD(T) with the ANO-RCC-Large basis sets. Standard enthalpies and Gibbs free energies of hydration were computed. The temperature dependence of Δ r G°(T) was evaluated for the most stable complexes over the temperature range 200−400 K. Thermodynamic data revealed that the highest fraction hydrated at 298 K and 100% relative humidity will be BrHgNO 2 −H 2 O at ∼5%.

Quantum Chemical Investigation of Snow–Mercury Interactions and Their Implication of Mercury Deposition in the Arctic

“…However, an important feature to note is that oxygen atoms from mercury molecules lead to a stronger interaction through an O−H surface bond as opposed to halogen or hydrogen atoms (e.g., BrHgXO has stronger adsorption than BrHgOX, see Table 1). Taamalli and co-workers 82 reported the reaction enthalpies between a water molecule and BrHgOH, BrHgO 2 H, BrHgNO 2 , syn-BrHgONO, and anti-BrHgONO using three different levels of theory, ωB97XD/aug-cc-pVTZ, DK-CCSD-(T)/ANO-RCC-Large, and DK-CCSD(T)-cf/ANO-RCC-Large. The one-to-one comparison of our calculated values to these are not compatible as optimized structures are not the same.…”