Calculation of IR Spectra with a Fully Polarizable QM/MM Approach Based on Fluctuating Charges and Fluctuating Dipoles

Tommaso Giovannini; Laura Grazioli; Matteo Ambrosetti; Chiara Cappelli

doi:10.1021/acs.jctc.9b00574

Calculation of IR Spectra with a Fully Polarizable QM/MM Approach Based on Fluctuating Charges and Fluctuating Dipoles

J Chem Theory Comput. 2019 Oct 8;15(10):5495-5507. doi: 10.1021/acs.jctc.9b00574. Epub 2019 Sep 6.

Authors

Tommaso Giovannini¹, Laura Grazioli², Matteo Ambrosetti², Chiara Cappelli²

Affiliations

¹ Department of Chemistry , Norwegian University of Science and Technology , Trondheim 7491 , Norway.
² Scuola Normale Superiore , Piazza dei Cavalieri 7 , Pisa 56126 , Italy.

PMID: 31436976
DOI: 10.1021/acs.jctc.9b00574

Abstract

The fully polarizable QM/MM approach based on fluctuating charges and fluctuating dipoles, named QM/FQFμ (J. Chem. Theory Comput. 2019, 15, 2233-2245), is extended to the evaluation of nuclear gradients and the calculation of IR spectra of molecular systems in condensed phase. To this end, analytical equations defining first and second energy derivatives with respect to nuclear coordinates are derived and discussed. The potentialities of the approach are shown by applying the model to the calculation of IR spectra of methlyoxirane, glycidol, and gallic acid in aqueous solution. The results are compared to the continuum QM/PCM and the polarizable QM/FQ, which is based on fluctuating charges only.