In our recent work (D'haese, L. C. G.; et al., Spectrochim. Acta, Part A 2024, 306, 123484), we have studied the cryptophane-111 system and observed a peculiar behavior on the relative energies of its conformers, induced by the addition of empirical dispersion corrections to our original method, B3LYP. Then, we have decided to deeply investigate the addition of different corrections to B3LYP, namely, the empirical dispersion corrections and the long-range corrections. We have observed systematic behaviors while increasing the amount of constant Hartree-Fock (HF) exchange, increasing the final amount of HF exchange, and increasing the coefficient ω. However, some changes have opposite effects on the conformations and normal modes. Thanks to these observations, we have identified two specific regions where the increase of the HF exchange has different impacts, namely, the short-range interatomic distance and the long-range interatomic distance. Concerning the normal modes, we have noticed interesting results while adding the empirical dispersion corrections, even though they lead to poor Boltzmann weights.
D’haese et al. (Thu,) studied this question.