Ab initio Hartree-Fock study on surface desorption process in tritium release

Dissociative adsorption of hydrogen on Li2O (110) surface has been investigated with ab initio Hartree-Fock quantum chemical calculation technique. Heat of adsorption and surface potential energy for H2 dissociative adsorption were evaluated by calculating the total energy of the system. The calculated results on adsorption heat indicated that H2 adsorption is endothermic. However, when an oxygen vacancy exists adjacent to the adsorption site, the heat of adsorption became less endothermic and the activation energy required to dissociate the H-H bonding was smaller than that for the terrace site. This is considered to be caused by the excess charge localized near the defect. (orig.)