Correlated ab initio study of the ground electronic state of the O2–HF complex

In this paper, we present the first correlated ab initio investigations on the ground electronic state of the O2–HF complex. Calculations were performed using the CCSD(T) method with the aug-cc-pVDZ and aug-cc-pVTZ basis sets. The results show that there are two equivalent minimum energy hydrogen-bonded structures of planar bent geometry, where the minima correspond to exchange of the oxygen atoms. For each minimum the length of the O–H hydrogen bond is 2.16A. The best calculated value of De of the equivalent minima is 271cm−1. The T-shaped geometry of the complex, with oxygen perpendicular to the axis connecting the center of masses of O2 and the HF molecule, represents a barrier to tunneling between the equivalent minima. The best estimated value of that barrier height is 217cm−1. The linear O–O–HF geometry of the complex represents a saddle point. The calculated geometrical parameters of the minimum energy structure of the complex are in reasonable agreement with the previously reported spectroscopic r...