### Abstract

Fluctuations of the dipole moment of a macroscopic dielectric sample are induced by thermal motions. The variance of the sample dipole moment, characterizing the extent of thermal fluctuations, is a decaying function of temperature for many polar liquids. This result is inconsistent with the Nyquist (fluctuation-dissipation) theorem predicting the variance of a macroscopic property to grow linearly with temperature. The reason for a qualitatively different behavior is in strong multi-particle correlations of dipolar orientations. An equation connecting the temperature slope of the dielectric constant to a static three-point correlation function is derived. When applied to experimental data for polar and hydrogen-bonding liquids at normal conditions, the three-point correlations of different liquids fall on a single master curve as a function of the dielectric constant. Static three-point correlation functions can potentially reflect the growing spatial correlation length on approach to the glass transition. However, the measured temperature slope of the dielectric constant of glycerol does not indicate a change in such a lengthscale.

Original language | English (US) |
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Article number | 041102 |

Journal | Journal of Chemical Physics |

Volume | 144 |

Issue number | 4 |

DOIs | |

State | Published - Jan 28 2016 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry

### Cite this

**Communication : Temperature derivative of the dielectric constant gives access to multipoint correlations in polar liquids.** / Matyushov, Dmitry; Richert, Ranko.

Research output: Contribution to journal › Article

}

TY - JOUR

T1 - Communication

T2 - Temperature derivative of the dielectric constant gives access to multipoint correlations in polar liquids

AU - Matyushov, Dmitry

AU - Richert, Ranko

PY - 2016/1/28

Y1 - 2016/1/28

N2 - Fluctuations of the dipole moment of a macroscopic dielectric sample are induced by thermal motions. The variance of the sample dipole moment, characterizing the extent of thermal fluctuations, is a decaying function of temperature for many polar liquids. This result is inconsistent with the Nyquist (fluctuation-dissipation) theorem predicting the variance of a macroscopic property to grow linearly with temperature. The reason for a qualitatively different behavior is in strong multi-particle correlations of dipolar orientations. An equation connecting the temperature slope of the dielectric constant to a static three-point correlation function is derived. When applied to experimental data for polar and hydrogen-bonding liquids at normal conditions, the three-point correlations of different liquids fall on a single master curve as a function of the dielectric constant. Static three-point correlation functions can potentially reflect the growing spatial correlation length on approach to the glass transition. However, the measured temperature slope of the dielectric constant of glycerol does not indicate a change in such a lengthscale.

AB - Fluctuations of the dipole moment of a macroscopic dielectric sample are induced by thermal motions. The variance of the sample dipole moment, characterizing the extent of thermal fluctuations, is a decaying function of temperature for many polar liquids. This result is inconsistent with the Nyquist (fluctuation-dissipation) theorem predicting the variance of a macroscopic property to grow linearly with temperature. The reason for a qualitatively different behavior is in strong multi-particle correlations of dipolar orientations. An equation connecting the temperature slope of the dielectric constant to a static three-point correlation function is derived. When applied to experimental data for polar and hydrogen-bonding liquids at normal conditions, the three-point correlations of different liquids fall on a single master curve as a function of the dielectric constant. Static three-point correlation functions can potentially reflect the growing spatial correlation length on approach to the glass transition. However, the measured temperature slope of the dielectric constant of glycerol does not indicate a change in such a lengthscale.

UR - http://www.scopus.com/inward/record.url?scp=84956966881&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84956966881&partnerID=8YFLogxK

U2 - 10.1063/1.4941089

DO - 10.1063/1.4941089

M3 - Article

VL - 144

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 4

M1 - 041102

ER -