Interaction of C2H with molecular hydrogen: Ab initio potential energy surface and scattering calculations

摘要

The potential energy surface (PES) describing the interaction of the ethynyl (C2H) radical in its ground (X) over tilde (2)Sigma(+) electronic state with molecular hydrogen has been computed through restricted coupled cluster calculations including single, double, and (perturbative) triple excitations [RCCSD(T)], with the assumption of fixed molecular geometries. The computed points were fit to an analytical form suitable for time-independent quantum scattering calculations of rotationally inelastic cross sections and rate constants. A representative set of energy dependent state-to-state cross sections is presented and discussed. The PES and cross sections for collisions of H-2(j = 0) are compared with a previous study [F. Najar et al., Chem. Phys. Lett. 614, 251 (2014)] of collisions of C2H with H-2 treated as a spherical collision partner. Good agreement is found between the two sets of calculations when the H-2 molecule in the present calculation is spherically averaged. Published by AIP Publishing.