Theoretical studies of three-dimensional potential energy surfaces using neural networks and rotational spectra of the Ar–N₂ complex

ABSTRACT

A new three-dimensional potential energy surface (PES) of the Ar–N₂ van der Waals complex is constructed using the neural network method based on ab initio data points at the CCSD(T) level. The aug-cc-pVQZ basis set is employed for all atoms with midbond functions. The vibrationally averaged PES V₀₀ is characterised by a global T-shaped minimum which occurs at R = 3.715 Å, θ = 90.0° with a well depth of 98.779 cm⁻¹. Based on our three-dimensional PES, bound-state calculations are performed for three isotopomers of Ar–¹⁴N₂, Ar–¹⁵N₂, and Ar–¹⁴N¹⁵N, and several intermolecular vibrational states are assigned by analysing the wavefunctions. Moreover, the averaged structural parameters are calculated and the pure rotational transition frequencies with J = 0--6 are predicted. The spectroscopic constants are determined by fitting the rotational energy levels. The theoretical results are in good agreement with experimental data and this work gives more accurate results than those determined previously for the Ar–N₂ complex.

KEYWORDS:

• Ar–N₂
• potential energy surface
• neural networks
• bound-state calculations
• spectroscopic parameters

Acknowledgements

The authors thank Prof. Minghui Yang for providing the computer used to perform the calculations in this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Science Foundation for Introducing Talent of Ningde Normal University (Grant No. 2013Y004); the Education and Research Foundation (Science and Technology) for Young Teachers of the Education Department of Fujian Province [Grant No. JA15557]; the Scientific Innovation Team Foundation of Ningde Normal University [Grant No. 2013T03]; the National Science Foundation of China [Grant No. 21303254]; the National Natural Science Foundation of China [Grant No. 11304095].