Modeling the linear and nonlinear dielectric response of solvents

Published

March 13, 2023

Author(s)

Michael Woodcox, Avik Mahata, Aaron Hagerstrom, Angela Stelson, Chris Muzny, Ravishankar Sundararaman, Kathleen Schwarz

Abstract

We demonstrate a method to compute the dielectric spectra of fluids in molecular dynamics by directly applying electric fields to the simulation. We obtain spectra from molecular dynamics simulations with low magnitude electric fields (0.01 V/A) in agreement with spectra from the fluctuation dissipation method for water and acetonitrile. We examine this method's tradeoff between noise at low field magnitudes and nonlinearity of the response at higher field magnitudes. We then apply the Booth equation to describe the nonlinear response of both fluids at low frequency (0.1 GHz) and high field magnitude (up to 0.5 V/A). We develop a model of the frequency-dependent nonlinear response by combining the Booth description of the static nonlinear dielectric response of fluids with the frequency-dependent linear dielectric response of the Debye model. We find good agreement between our model and the molecular dynamics (MD) simulations of the nonlinear dielectric response for both acetonitrile and water.

Citation

The Journal of Chemical Physics

Pub Type

Journals

Download Paper

https://doi.org/10.1063/5.0143425

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Citation

Woodcox, M. , Mahata, A. , Hagerstrom, A. , Stelson, A. , Muzny, C. , Sundararaman, R. and Schwarz, K. (2023), Modeling the linear and nonlinear dielectric response of solvents, The Journal of Chemical Physics, [online], https://doi.org/10.1063/5.0143425, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936096 (Accessed December 26, 2024)