Tailored anharmonic potential energy surfaces for infrared signatures

authored by: Janine Isabel Hellmers, Pascal Czember, Carolin König
Abstract: Accurately calculated infrared spectra are essential for supporting experimental interpretation, yet full-space anharmonic vibrational structure calculations are only feasible for a limited number of degrees of freedom. Fortunately, characteristic spectroscopic signatures are often dominated by a few key vibrations. We propose a computational protocol specifically tailoring high dimensional anharmonic potential energy surfaces for the accurate and efficient calculation of such spectral signatures with vibrational coupled cluster response theory. Our protocol focuses on the selection of appropriate coordinates for the relevant degrees of freedom and the identification of specific mode-coupling terms for the potential energy surface that require more thorough treatment. This includes applying different levels of electronic structure theory and selecting a restricted set of higher mode-coupling terms (> mode pairs). We validate this protocol on two spectral regions: the fundamental C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O stretching vibrations in uracil and the fundamental OH stretchings in catechol. Our findings indicate that the convergence behaviour towards harmonic frequencies in the so-called FALCON algorithm is an effective indicator for the locality character of the relevant degrees of freedom. We find that the C O stretchings in uracil are better described using normal coordinates, while the description with local FALCON coordinates of the OH-stretching vibrations in catechol showed superior performances in VCC spectra calculations. Overall, our protocol offers valuable guidelines for accurate and efficient anharmonic calculation of vibrational spectral signatures.
Organisation(s): Institute of Physical Chemistry and Electrochemistry
AG Computational Chemistry
Type: Article
Journal: Physical Chemistry Chemical Physics
Volume: 48
Pages: 29732–29748
ISSN: 1463-9076
Publication date: 25.11.2024
Publication status: E-pub ahead of print
Peer reviewed: Yes
Electronic version(s): https://doi.org/10.1039/d4cp02916j (Access: Open)

BibTeX

@article{b64f2c06227f41bc81774ceb8f179100,
title = "Tailored anharmonic potential energy surfaces for infrared signatures",
abstract = "Accurately calculated infrared spectra are essential for supporting experimental interpretation, yet full-space anharmonic vibrational structure calculations are only feasible for a limited number of degrees of freedom. Fortunately, characteristic spectroscopic signatures are often dominated by a few key vibrations. We propose a computational protocol specifically tailoring high dimensional anharmonic potential energy surfaces for the accurate and efficient calculation of such spectral signatures with vibrational coupled cluster response theory. Our protocol focuses on the selection of appropriate coordinates for the relevant degrees of freedom and the identification of specific mode-coupling terms for the potential energy surface that require more thorough treatment. This includes applying different levels of electronic structure theory and selecting a restricted set of higher mode-coupling terms (> mode pairs). We validate this protocol on two spectral regions: the fundamental C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O stretching vibrations in uracil and the fundamental OH stretchings in catechol. Our findings indicate that the convergence behaviour towards harmonic frequencies in the so-called FALCON algorithm is an effective indicator for the locality character of the relevant degrees of freedom. We find that the C O stretchings in uracil are better described using normal coordinates, while the description with local FALCON coordinates of the OH-stretching vibrations in catechol showed superior performances in VCC spectra calculations. Overall, our protocol offers valuable guidelines for accurate and efficient anharmonic calculation of vibrational spectral signatures.",
author = "Hellmers, {Janine Isabel} and Pascal Czember and Carolin K{\"o}nig",
note = "Publisher Copyright: {\textcopyright} 2024 The Royal Society of Chemistry.",
year = "2024",
month = nov,
day = "25",
doi = "10.1039/d4cp02916j",
language = "English",
volume = "48",
pages = "29732–29748",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
}