The automated development of a new ab initio full-dimensional potential energy surface (PES) is reported for the CH4⋅F− complex using the ROBOSURFER program package. The new potential provides a near-spectroscopic quality description over a broad configuration range including the methane-ion dissociation, as well as isolated methane vibrations. In particular, it improves upon the earlier [Czak\'o, Braams, Bowman (2008)] PES over intermediate methane-fluoride distances. Full-dimensional (12D) variational vibrational computations using the new PES and the GENIUSH-Smolyak algorithm show that tunneling splittings larger than 0.1 cm−1 appear below the top of the interconversion barrier of the four equivalent minima of the complex.
@article{arxiv.2209.04306,
title = {CH$_4\cdot$F$^-$ revisited: Full-dimensional ab initio potential energy surface and variational vibrational states},
author = {Dóra Papp and Viktor Tajti and Gustavo Avila and Edit Mátyus and Gábor Czakó},
journal= {arXiv preprint arXiv:2209.04306},
year = {2022}
}