Rotational Memory Function of SPC/E water

Fuente: arXiv
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Auteurs principaux: Asthagiri, Dilipkumar N., Matyushov, Dmitry V.
Format: Preprint
Publié: 2026
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author Asthagiri, Dilipkumar N.
Matyushov, Dmitry V.
author_facet Asthagiri, Dilipkumar N.
Matyushov, Dmitry V.
contents Memory effects are essential for dynamics of condensed materials and are responsible for non-exponential relaxation of correlation functions of dynamic variables through the memory function. Memory functions of dipole rotations for polar liquids have never been calculated. We present here calculations of memory functions for single-dipole rotations and for the overall dipole moment of the sample for SPC/E water. The memory functions for single-particle and collective dipole dynamics turn out to be nearly identical. This result validates theories of dielectric spectroscopy in terms of single-particle time correlation functions and the connection between the collective and single-particle relaxation times through the Kirkwood factor. The dielectric function in this formalism contains no new dynamic information that does not exist in the single-dipole correlation function. A short memory time, $\lesssim 1$ fs, justifies the use of rotational diffusion model to describe dynamics of a single molecular dipole moment in bulk water.
format Preprint
id arxiv_https___arxiv_org_abs_2601_10022
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rotational Memory Function of SPC/E water
Asthagiri, Dilipkumar N.
Matyushov, Dmitry V.
Statistical Mechanics
Chemical Physics
Memory effects are essential for dynamics of condensed materials and are responsible for non-exponential relaxation of correlation functions of dynamic variables through the memory function. Memory functions of dipole rotations for polar liquids have never been calculated. We present here calculations of memory functions for single-dipole rotations and for the overall dipole moment of the sample for SPC/E water. The memory functions for single-particle and collective dipole dynamics turn out to be nearly identical. This result validates theories of dielectric spectroscopy in terms of single-particle time correlation functions and the connection between the collective and single-particle relaxation times through the Kirkwood factor. The dielectric function in this formalism contains no new dynamic information that does not exist in the single-dipole correlation function. A short memory time, $\lesssim 1$ fs, justifies the use of rotational diffusion model to describe dynamics of a single molecular dipole moment in bulk water.
title Rotational Memory Function of SPC/E water
topic Statistical Mechanics
Chemical Physics
url https://arxiv.org/abs/2601.10022