Theoretical study of the kinetics of the reactions Se + O2 --> Se + O and As + HCl --> AsCl + H.

Selenium and arsenic reactions believed to take place in the flue gases of coal combustion facilities were investigated. Prior theoretical work involving various As and Se species was completed using DFT and a broad range of ab initio methods. Building upon that work, the present study is a determination of the kinetic and thermodynamic parameters of the reactions, Se + O2 --> SeO + O and As + HCl --> AsCl + H at the CCSD/RCEP28VDZ and QCISD(T)/6-311++G(3df,3pd) levels of theory, respectively. Transition state theory was used in determining the kinetic rate constants along with collision theory as a means of comparison. The calculated K(eq) values are compared to experimental data, where available.

A theoretical study of properties and reactions involving arsenic and selenium compounds present in coal combustion flue gases.

Species of arsenic and selenium thought to be present in coal combustion flue gases were studied using density functional theory and a broad range of ab initio methods. At each level of theory, the calculated geometries and vibrational frequencies of each species as well as the reaction enthalpies of anticipated reactions were compared with experimental data where available. Comparisons between each calculation are given along with a discussion of the better performance of some theoretical calculations for a given species/reaction.