Communication: High pressure specific heat spectroscopy reveals simple relaxation behavior of glass forming molecular liquid

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Resumé

The frequency dependent specific heat has been measured under pressure for the molecular glass forming liquid 5-polyphenyl-4-ether in the viscous regime close to the glass transition. The temperature and pressure dependences of the characteristic time scale associated with the specific heat is compared to the equivalent time scale from dielectric spectroscopy performed under identical conditions. It is shown that the ratio between the two time scales is independent of both temperature and pressure. This observation is non-trivial and demonstrates the existence of specially simple molecular liquids in which different physical relaxation processes are both as function of temperature and pressure/density governed by the same underlying “inner clock.” Furthermore, the results are discussed in terms of the recent conjecture that van der Waals liquids, like the measuredliquid, comply to the isomorph theory
OriginalsprogEngelsk
Artikelnummer221101
TidsskriftJournal of Chemical Physics
Vol/bind143
ISSN0021-9606
DOI
StatusUdgivet - 9 dec. 2015

Citer dette

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title = "Communication: High pressure specific heat spectroscopy reveals simple relaxation behavior of glass forming molecular liquid",
abstract = "The frequency dependent specific heat has been measured under pressure for the molecular glass forming liquid 5-polyphenyl-4-ether in the viscous regime close to the glass transition. The temperature and pressure dependences of the characteristic time scale associated with the specific heat is compared to the equivalent time scale from dielectric spectroscopy performed under identical conditions. It is shown that the ratio between the two time scales is independent of both temperature and pressure. This observation is non-trivial and demonstrates the existence of specially simple molecular liquids in which different physical relaxation processes are both as function of temperature and pressure/density governed by the same underlying “inner clock.” Furthermore, the results are discussed in terms of the recent conjecture that van der Waals liquids, like the measuredliquid, comply to the isomorph theory",
author = "Roed, {Lisa Anita} and Kristine Niss and Bo Jakobsen",
year = "2015",
month = "12",
day = "9",
doi = "10.1063/1.4936867",
language = "English",
volume = "143",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics",

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T1 - Communication: High pressure specific heat spectroscopy reveals simple relaxation behavior of glass forming molecular liquid

AU - Roed, Lisa Anita

AU - Niss, Kristine

AU - Jakobsen, Bo

PY - 2015/12/9

Y1 - 2015/12/9

N2 - The frequency dependent specific heat has been measured under pressure for the molecular glass forming liquid 5-polyphenyl-4-ether in the viscous regime close to the glass transition. The temperature and pressure dependences of the characteristic time scale associated with the specific heat is compared to the equivalent time scale from dielectric spectroscopy performed under identical conditions. It is shown that the ratio between the two time scales is independent of both temperature and pressure. This observation is non-trivial and demonstrates the existence of specially simple molecular liquids in which different physical relaxation processes are both as function of temperature and pressure/density governed by the same underlying “inner clock.” Furthermore, the results are discussed in terms of the recent conjecture that van der Waals liquids, like the measuredliquid, comply to the isomorph theory

AB - The frequency dependent specific heat has been measured under pressure for the molecular glass forming liquid 5-polyphenyl-4-ether in the viscous regime close to the glass transition. The temperature and pressure dependences of the characteristic time scale associated with the specific heat is compared to the equivalent time scale from dielectric spectroscopy performed under identical conditions. It is shown that the ratio between the two time scales is independent of both temperature and pressure. This observation is non-trivial and demonstrates the existence of specially simple molecular liquids in which different physical relaxation processes are both as function of temperature and pressure/density governed by the same underlying “inner clock.” Furthermore, the results are discussed in terms of the recent conjecture that van der Waals liquids, like the measuredliquid, comply to the isomorph theory

U2 - 10.1063/1.4936867

DO - 10.1063/1.4936867

M3 - Journal article

VL - 143

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

M1 - 221101

ER -