Theoretical study of the CO-O van der Waals complex: potential energy surface and applications

• Published in: Physical chemistry chemical physics : PCCP 2022-12, Vol.24 (47), p.28984-28993
• Main Authors: Ajili, Yosra, Quintas-Sánchez, Ernesto, Mehnen, Bilel, uchowski, Piotr S, Brz k, Filip, El-Kork, Nayla, Gacesa, Marko, Dawes, Richard, Hochlaf, Majdi
• Format: Article
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d2cp04101d

A four-dimensional-potential energy surface (4D-PES) of the atmospherically relevant carbon dioxide-oxygen molecule (CO 2 -O 2 ) van der Waals complex is mapped using the ab initio explicitly correlated coupled cluster method with single, double, and perturbative triple excitations (UCCSD(T)-F12b), and extrapolation to the complete basis set (CBS) limit using the cc-pVTZ-F12/cc-pVQZ-F12 bases and the l −3 formula. An analytic representation of the 4D-PES was fitted using the method of interpolating moving least squares (IMLS). These calculations predict that the most stable configuration of CO 2 -O 2 complex corresponds to a planar slipped-parallel structure with a binding energy of V ∼ −243 cm −1 . Another isomer is found on the PES, corresponding to a non-planar cross-shaped structure, with V ∼ −218 cm 1 . The transition structure connecting the two minima is found at V ∼ 211 cm 1 . We also performed comparisons with some CO 2 -X van der Waals complexes. Moreover, we provide a SAPT analysis of this molecular system. Then, we discuss the complexation induced shifts of CO 2 and O 2 . Afterwards, this new 4D-PES is employed to compute the second virial coefficient including temperature dependence. A comparison between quantities obtained in our calculations and those from experiments found close agreement attesting to the high quality of the PES and to the importance of considering a full description of the anisotropic potential for the derivation of thermophysical properties of CO 2 -O 2 mixtures. A four-dimensional-potential energy surface (4D-PES) of the atmospherically relevant CO 2 -O 2 van der Waals complex is generated using ab initio methodology. Induced complexation shifts and second virial coefficient are also presented.