A FURTHER THEORETICAL EXPLORATION OF THE SURFACE-ALIGNED PHOTO-INITIATED H+CO2 REACTION - SURFACE MOTION AND TEMPERATURE DEPENDENCE

摘要

We report a further theoretical investigation of a model surface-aligned photoreaction with a moving surface approximation, The reaction is initiated by the photodissociation of a well-aligned HBr adsorbed on the LiF(001) surface. The collision of the dissociating H fragment with a coadsorbed CO2 leads to the DH and CO products. In an earlier theoretical study with a static surface model, it has been shown that the reactivity can be significantly enhanced relative to the corresponding gas phase reaction for some adsorption alignments. In this work, we address the roles played by surface motion and temperature. Our results indicate that some (similar to 0.3 eV) energy can be lost to the surface either from the adsorbed HOCO complex or from one of the products when it collides with the surface during the final disintegration of the HOCO complex. However, the energy transfer has a minor effect on the reactivity. The final state distributions of the products are found to be similar to those produced with the static surface model. On the other hand, a significant temperature effect is predicted for one adsorbate configuration. Apparently, the lowering of temperature for a well-aligned system results in a more narrowly focused alignment and higher reactivity. (C) 1997 American Institute of Physics. [References: 40]