A Mössbauer Temperature Study of 1,1′-diacetylferrocene in the Liquid Crystal, N-(P-hexyloxybenzylidene)-P-toluidine
作者:
RobertP. Marande,
Nathan Viswanathan,
期刊:
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
(Taylor Available online 1998)
卷期:
Volume 312,
issue 1
页码: 247-252
ISSN:1058-725X
年代: 1998
DOI:10.1080/10587259808042444
出版商: Taylor & Francis Group
关键词: Mössbauer Effect;liquid crystal;diacetylferrocene
数据来源: Taylor
摘要:
The Fe-57 Mössbauer Effect was used to study a solution (0.2% by Weight) of 1,1′-diacetylferrocene (DAF) in the liquid crystalline materialp-n-hexyloxy-benzylidene-p-toluidine (HBT). The DAF contained enriched Fe-57. The Mössbauer Effect parameters were determined for the temperature range 100–300K in the crystalline solid phase and 100–200K in the cold smectic ß phase of HBT. Here “cold” means the smectic glass and the supercoded smectic phase. The Ln recoil-free intensity (f)vsTdata exhibited linear Debye behavior for the solid phase over the entire temperature range. The low temperature (T< 190) portion of the cold smectic InfvsTdata also exhibited Debye behavior, and the smectic glass gave a Mössbauer-Debye temperature (θlc) about 30 K. lower than the crystalline phase. The smectic glass-super cooled smectic transition was determined to beTg= 190 K from the deviation of the InfvsTdata from linear behavior. AboveTg, the deviation from linear Debye behavior followed a (T-Tg)2dependence. The smecticBglass yielded an order parameter ofS= 0.06 for DAF molecules at 100 K. Rotational and transitional diffusion were not observed for the cold smecticBphase.
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