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Classical molecular dynamics simulations of diamond surface reactions were performed using quantum mechanically derived forces. A semiempirical AM 1 potential from the MOPAC quantum-chemistry program package was employed in the calculations. The evolving molecular geometry, energetics, bond orders, and vibrational frequencies were monitored. The conformation and bond breaking of a surface step, examples of reactions of gaseous species with the diamond ( 1 1 1) surface, and reactions of free gaseous analogs were examined. One of the main findings is the existence of a trapped, physisorption state for an acetylene molecule colliding with a diamond surface at a temperature typical of diamond CVD. The hypothesis of chemical similarity between the rate constants for gas-surface and analogous gas-phase reactions is addressed. The results obtained indicate that although a considerable similarity indeed exists, significant quantitative differences are induced by the confinement of the surface.

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