Reaction dynamics of H2 on Si. Ab initio supported model calculations

Hydrogen molecules associatively desorbing from Si(0 0 1) surfaces were observed to have low kinetic energies in spite of a high adsorption barrier needed to explain the low sticking coefficient of the same molecules. This apparent violation of the principle of detailed balance was called the barrier puzzle in 1994 and has initiated a decade of intensive research leading to a detailed microscopic understanding of the reaction mechanisms. It turned out that the covalent Si-Si and Si-hydrogen bonding induces a rather complex adsorption/desorption scenario: Substrate mediated hydrogen-phonon, and hydrogen-hydrogen interactions are ail order of magnitude bigger than oil metals and lead to strong dependencies of sticking coefficients oil substrate temperature and coverage. Now after 13 years a certain plateau of our knowledge has been reached and justifies (another) review of theoretical investigations and results. It presents ail updated and extended version of two sections of ail earlier review by one of the authors oil Quantum Dynamical calculations of H-2 on Si(0 0 1), a section on ab initio calculations of potential surfaces and a section oil the effect of Substrate mediated hydrogen-hydrogen interactions at high coverages using Non-equilibrium Statistical Physics. (C) 2008 Elsevier Ltd. All rights reserved.