A global CHIPR potential energy surface for ground-state C 3 H and exploratory dynamics studies of reaction C 2 + CH → C 3 + H

• Published in: Physical chemistry chemical physics : PCCP 2019-11, Vol.21 (44), p.24406-24418
• Main Authors: Rocha, C. M. R., Varandas, A. J. C.
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/C9CP04890A

A full-dimensional global potential-energy surface (PES) is first reported for ground-state doublet C 3 H using the combined-hyperbolic-inverse-power-representation (CHIPR) method and accurate ab initio energies extrapolated to the complete basis set limit. The PES is based on a many-body expansion-type development where the two-body and three-body energy terms are from our previously reported analytic potentials for C 2 H( 2 A′) and C 3 ( 1 A′, 3 A′), while the effective four-body one is calibrated using an extension of the CHIPR formalism for tetratomics. The final form is shown to accurately reproduce all known stationary structures of the PES, some of which are unreported thus far, and their interconversion pathways. Moreover, it warrants by built-in construction the appropriate permutational symmetry and describes in a physically reasonable manner all long-range features and the correct asymptotic behavior at dissociation. Exploratory quasi-classical trajectory calculations for the reaction C 2 + CH → C 3 + H are also performed, yielding thermalized rate coefficients for temperatures up to 4000 K.