Interaction of H 2 O with CO: potential energy surface, bound states and scattering calculations

Y. Kalugina , A. Faure (1) , A. van Der Avoird , K. Walker , François Lique (2)

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
2 LOMC - Laboratoire Ondes et Milieux Complexes

Collisions between H2O and CO play a crucial role in the gaseous component of comets and protoplanetary disks. We present here a five-dimensional potential energy surface (PES) for the H2O–CO collisional complex. Ab initio calculations were carried out using the explicitly-correlated closed-shell single- and double-excitation coupled cluster approach with the non-iterative perturbative treatment of triple excitations [CCSD(T)-F12a] method with the augmented correlation-consistent aug-cc-pVTZ basis sets. The most stable configuration of the complex, where the carbon atom of CO is pointing towards the OH bond of water, has a binding energy De = 646.1 cm−1. The end-over-end rotational constant of the H2O–CO complex was extracted from bound state calculations and it was found to be B0 = 0.0916 cm−1, in excellent agreement with experimental measurements. Finally, cross sections for the rotational excitation of CO by H2O are computed for s-wave (J = 0) scattering at the full close-coupling level of theory. These results will serve as a benchmark for future studies.

Domaines: Physique [physics]

Y. Kalugina, A. Faure, A. van Der Avoird, K. Walker, François Lique. Interaction of H 2 O with CO: potential energy surface, bound states and scattering calculations. Physical Chemistry Chemical Physics, 2018, 20 (8), pp.5469-5477. ⟨10.1039/c7cp06275c⟩. ⟨hal-03045132⟩