A potential energy surface for the ground state of acetylene, C2H2

Carter, S., Mills, I. and Murrell, J. N. (1980) A potential energy surface for the ground state of acetylene, C2H2. Journal of Molecular Physics, 41 (1). pp. 191-203. ISSN 0026-8976 doi: 10.1080/00268978000102681

Abstract/Summary

A potential energy function has been derived for the ground state surface of C2H2 as a many-body expansion. The 2- and 3-body terms have been obtained by preliminary investigation of the ground state surfaces of CH2( 3B1) and C2H( 2Σ+). A 4-body term has been derived which reproduces the energy, geometry and harmonic force field of C2H2. The potential has a secondary minimum corresponding to the vinylidene structure and the geometry and energy of this are in close agreement with predictions from ab initio calculations. The saddle point for the HCCH-H2CC rearrangement is predicted to lie 2•530 eV above the acetylene minimum.