Anharmonicity in Molecular Crystals: Generalized Perturbation Theory Meets Periodic Computations.

ABSTRACT: Accurate simulation of vibrational spectra in the solid state remains a major challenge due to the combined effects of anharmonicity, intermolecular interactions, and resonance phenomena. In this work, we introduce a generalized second-order vibrational perturbation theory (GVPT2) framework for the quantitative computational spectroscopy of molecular solids. The method balances efficiency and accuracy through a perturb-then-diagonalize approach in which resonant terms are excluded in the initial perturbative treatment and subsequently handled more accurately through a variational approach. This strategy ensures numerical stability while capturing essential vibrational couplings. As a representative application, we investigated the infrared spectrum of solid carbon dioxide (dry ice), a prot

SUBMITTER: Mitoli D 

PROVIDER: S-EPMC12478864 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature