Elementary reaction mechanism of diamond growth from acetylene

TLDR: In this paper, the growth of diamond from acetylene is explained by the addition of an acetylene molecule that forms a bridge between adjacent (100)-(2x1) dimer rows, where the admolecule can undergo a series of H-additions, H-abstractions, and [beta]-scissions.

Abstract: Kinetically and thermodynamically plausible reactions that can explain the growth of diamond from acetylene are introduced. This class of reactions includes the addition of acetylene to a biradical with at least one of its sites being either a (100)-(2x1) dimer carbon or a secondary carbon, so that the admolecule can undergo a series of H-additions, H-abstractions, and [beta]-scissions leading to incorporation of its carbon atoms into a diamond lattice. Several examples are presented and supported with the results of semiempirical quantum-chemical and transition-state-theory calculations. Among those considered, the most favorable reaction pathway is initiated by the addition of an acetylene molecule that forms a bridge between adjacent dimer rows. 34 refs., 2 figs., 1 tab.