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

• Published in: Astrophysics and space science 2018-03, Vol.363 (3), p.1-7
• Main Authors: Tchakoua, Théophile, Pamboundom, Mama, Vamhindi, Berthelot Said Duvalier Ramlina, Engo, Serge Guy Nana, Motapon, Ousmanou, Nsangou, Mama
• Format: Article
• Language: English
• Subjects: Astrobiology; Astronomy; Astrophysics; Astrophysics and Astroparticles; Coefficients; Collisions; Cosmology; Cross-sections; Low temperature; Observations and Techniques; Original Article; Physics; Physics and Astronomy; Potential energy; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics
• ISSN: 0004-640X; 1572-946X
• DOI: 10.1007/s10509-018-3270-9

The potential energy surface (PES) for the CP ( X 2 Σ + ) - He ( 1 S ) complex has been calculated at the RCCSD(T)-F12/VTZ-F12 level of theory. The analytic fit of the PES was obtained by using global analytical method. The 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 CP-He complex. Collision energies were taken up to 1500 cm −1 and they yield after thermal averaging, state-to-state rate coefficients up to 200 K. The propensity rules between the lowest fine-structure levels were studied. These rules show, on one hand, a strong propensity in favour of even Δ N transitions, and the other hand, that cross sections and collisional rate coefficients for Δ j = Δ N transitions are larger than those for Δ j ≠ Δ N transitions.