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Hauptverfasser: Negishi, Naoki, Yokogawa, Daisuke
Format: Preprint
Veröffentlicht: 2024
Schlagworte:
Online-Zugang:https://arxiv.org/abs/2412.07376
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author Negishi, Naoki
Yokogawa, Daisuke
author_facet Negishi, Naoki
Yokogawa, Daisuke
contents We formulate frequency fluctuations of intramolecular vibrations of a solute by exploring the fluctuation of the electrostatic potential by solvents. We present a numerical methodology for estimating the frequency fluctuations; the methodology is based on the reference interaction site model self-consistent field with constrained spatial electron density distribution, a the theoretical model of solvation fields based on classical statistic mechanics. By applying the present theory to the C--N stretching vibrations of several nitrile compounds, our estimated frequency fluctuation scale and bandwidth shift by changing solvent kinds reproduced the experimental data. Further, we regard the standard deviation of the electrostatic potential as the multiple random variables for analyzing the frequency fluctuations. Our results reveal that the dominant fluctuation of the electrostatic field is almost parallel to the vibrational axis. Additionally, the fluctuations of electrostatic potential become spatially nonuniform as the solvents form stronger hydrogen bonds with the solute. The development of the solvation field confirms that the nonuniformity of the electrostatic field is crucial to the frequency fluctuation.
format Preprint
id arxiv_https___arxiv_org_abs_2412_07376
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Theory of Frequency Fluctuation of Intramolecular Vibration in Solution Phase: Application to C--N Stretching Mode of Organic Compounds
Negishi, Naoki
Yokogawa, Daisuke
Chemical Physics
We formulate frequency fluctuations of intramolecular vibrations of a solute by exploring the fluctuation of the electrostatic potential by solvents. We present a numerical methodology for estimating the frequency fluctuations; the methodology is based on the reference interaction site model self-consistent field with constrained spatial electron density distribution, a the theoretical model of solvation fields based on classical statistic mechanics. By applying the present theory to the C--N stretching vibrations of several nitrile compounds, our estimated frequency fluctuation scale and bandwidth shift by changing solvent kinds reproduced the experimental data. Further, we regard the standard deviation of the electrostatic potential as the multiple random variables for analyzing the frequency fluctuations. Our results reveal that the dominant fluctuation of the electrostatic field is almost parallel to the vibrational axis. Additionally, the fluctuations of electrostatic potential become spatially nonuniform as the solvents form stronger hydrogen bonds with the solute. The development of the solvation field confirms that the nonuniformity of the electrostatic field is crucial to the frequency fluctuation.
title Theory of Frequency Fluctuation of Intramolecular Vibration in Solution Phase: Application to C--N Stretching Mode of Organic Compounds
topic Chemical Physics
url https://arxiv.org/abs/2412.07376