A full-dimensional ab initio potential energy surface and rovibrational energies of the Ar–HF complex

ABSTRACT

We report a new full-dimensional ab initio potential energy surface for the Ar–HF van der Waals complex at the level of coupled-cluster singles and doubles with noniterative inclusion of connected triples levels [CCSD(T)] using augmented correlation-consistent quintuple-zeta basis set (aV5Z) plus bond functions. Full counterpoise correction was employed to correct the basis-set superposition error. The hypersurface was fitted using artificial neural network method with a root mean square error of 0.1085 cm⁻¹ for more than 8000 ab initio points. The complex was found to prefer a linear Ar–H–F equilibrium structure. The three-dimensional discrete variable representation method and the Lanczos propagation algorithm were then employed to calculate the rovibrational states without separating inter- and intra- molecular nuclear motions. The calculated vibrational energies of Ar–HF differ from the experiment values within about 1 cm⁻¹ on the first four HF vibrational states, and the predicted pure rotational energies on (0000) and (1000) vibrational states are deviated from the observed value by about 1%, which shows the accuracy of our new PES.

GRAPHICAL ABSTRACT

KEYWORDS:

• Ar–HF
• potential energy surface
• rovibrational energy

Acknowledgments

This work is supported by the National Natural Science Foundation of China (Grant Nos. 21590802, 21733006 and 91421315). We are very grateful to Prof. Jeremy M. Hutson for the FORTRAN code of potential H6(4,3,2).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

National Natural Science Foundation of China [grant numbers 21590802, 21733006 and 91421315]