摘要: Two aspects of molecular decomposition on MgO(l00) surfaces were explored.Nitrogen dioxide entrained in a molecular beam was photoexcited and directed at a crystal surface. It had enough internal plus translational energy to under... 展开 Two aspects of molecular decomposition on MgO(l00) surfaces were explored.Nitrogen dioxide entrained in a molecular beam was photoexcited and directed at a crystal surface. It had enough internal plus translational energy to undergo dissociation. The NO products, which were detected with state and angular resolution, were scattered preferentially in the specular direction and their internal energies were analyzed. The results showed that the collisional dissociation was rather efficient when the molecules possessed internal energies approaching dissociation energy. The photochemistry of ClNO was examined on an insulator metal oxide and compared with the analogous gaseous phase photodissociation; a large, qualitative difference was observed. Defect-laden and relatively defect-free MgO(l00) surfaces were used. Gas phase 355 nm photolysis yielded NO with a rotational distribution peaked sharply at N =42, whereas adsorbed ClNO always yielded NO with N < 10. The results suggested that ClNO aggregated on the surface in a way that affects photon-induced processes. jg p.1. 收起