11654
J. Phys. Chem. 1996, 100, 11654-11663
Theoretical Studies of Growth of Diamond (110) from Dicarbon† Paul C. Redfern,‡ David A. Horner,§ Larry A. Curtiss,*,‡ and Dieter M. Gruen‡ Argonne National Laboratory, Argonne, Illinois 60439, and North Central College, P.O. Box 3063, NaperVille, Illinois 60566 ReceiVed: October 27, 1995; In Final Form: April 9, 1996X
A mechanism for growth on the diamond (110) surface, with dicarbon (C2) as the growth species, is examined. Reaction energies and activation energies of the various steps in the mechanism were investigated on model systems using molecular quantum mechanics, including the AM1 semiempirical method and the BLYP/631G* density functional method. The BLYP/6-31G* method yielded reaction energies and activation barriers in reasonable agreement with the results of G2 theory on some simple, related reactions. Two models for a hydrogen-terminated diamond (110) surface were employed, one with 18 carbon atoms (C18H26) and another with 46 carbon atoms (C46H50). The results indicate that C2 addition to diamond (110) is highly exothermic with small activation barriers (
