Rotational cross sections and rate coefficients of aluminium monoxide AlO( X2Σ+) induced by its collision with He(1S) at low temperature

We present the first potential energy surface (PES) for the AlO(X-2 Sigma(+))-He(S-1) van der Waals complex. This PES has been calculated at the RCCSD(T) level of theory. The mixed Gaussian/Exponential Extrapolation Scheme of complete basis set [CBS(D, T, Q)] was employed. The PES was fitted using global analytical method. This fitted PES was used subsequently in the close-coupling approach for the computation of the state-to-state collisional excitation cross sections of the fine-structure levels of the AlO-He complex. Collision energies were taken up to 2500 cm(-1) and they yield after thermal averaging, state-to-state rate coefficients up to 300 K. The propensity rules between the lowest fine-structure levels were studied. These rules show, on one hand, a strong propensity in favour of odd Delta N transitions, and on the other hand, that cross sections and collisional rate coefficients for Delta j = Delta N transitions are larger than those for Delta j not equal Delta N transitions. (C) 2018 Elsevier B.V. All rights reserved.