Vibrationally excited intermolecular potential energy surfaces and the predicted near infrared overtone ( = 2 ← 0) spectra of a HO-Ne complex.

The intra- and inter-molecular potential energy surfaces (PESs) for the HO-Ne system that explicitly incorporate the intramolecular overtone state ( = 2) of HO are presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster theory [CCSD(T)-F12] level with an augmented correlation-consistent triple zeta basis set and an additional bond function. The vibrationally averaged three-dimensional intermolecular potentials for |00〉, |02〉, |02〉 and |11〉 are obtained analytically by fitting to the multi-dimensional Morse/Long-range potential function form. These fits to 46 980 points have a root-mean-square (RMS) discrepancy of 0.12 cm for interaction energies less than 1000.0 cm. With the vibrationally averaged PESs for the HO-Ne, we employed the combined radial discrete variable representation/angular finite basis representation method and Lanczos algorithm to calculate rovibrational energy levels ( = 0-10, ≤ 2). The predicted infrared transitions and intensities of the - and -HO-Ne complex are in good agreement with the available experimental data for |02〉 ← |00〉, |02〉 ← |00〉 transitions. In particular, the RMS discrepancy for |02〉∑(0,0) ← |00〉∑(1,0), including and branch patterns, is only 0.045 cm, which is comparable with the experimental values. These results will provide reliable theoretical guidance for the future infrared overtone spectroscopy of clusters.