REACTION OF GAS-PHASE ATOMIC-HYDROGEN WITH CHEMISORBED HYDROGEN-ATOMSON AN IRON SURFACE

The reaction of gas-phase atomic hydrogen with hydrogen atoms chemisor bed on Fe(110) surface is studied by use of classical trajectory proce dures. Flow of energy between the reaction zone and bulk solid phase h as been treated in the generalized Langevin equation approach. A Londo n-Eyring-Polanyi-Sato energy surface is used for the reaction zone int eraction. Most reactive events are found to occur in strong single-imp act collisions on a subpicosecond scale via the Eley-Rideal mechanism. The extent of reaction is large and a major fraction of the available energy goes into the vibrational excitation of H-2, exhibiting a vibr ational population inversion. Dissipation of reaction energy to the he at bath can be adequately described using a seven-atom chain with the chain end bound to the rest of solid. The extent of reaction is not se nsitive to the variation of surface temperature in the range of T-s=0- 300 K in the fixed gas temperature, but it shows a minimum near 1000 K over the T-g=300-2500 K.