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Mössbauer studies of DNF and FMA in a smectic B liquid crystal

 

作者: RobertP. Marande,   Nathan Viswanathan,  

 

期刊: Liquid Crystals  (Taylor Available online 1995)
卷期: Volume 19, issue 5  

页码: 637-642

 

ISSN:0267-8292

 

年代: 1995

 

DOI:10.1080/02678299508031078

 

出版商: Taylor & Francis Group

 

数据来源: Taylor

 

摘要:

The FE-57 Mössbauer effect (ME) was used to study two solutions 0.4 wt% of ferrocenyl-4′-methoxyaniline (FMA) in the liquid crystalline material 4-n-butoxybenzylidene-4′-n-octylaniline (40.8) and 0.4 wt% of 1,1′-dinonanoyl-ferrocence in 40.8. The ME parameters were determined for the temperature range 40-300 K in the crystalline solid phase and 40–220 K in the cold smectic B phase of 40.8 for both samples. The ‘cold smectic B’ is defined as the smectic B glass and the supercooled smectic B phase. ForT< 60 K the DNF-40.8 system exhibited a ME spectrum that was composed of two quadrupole split doublets. This four-line spectrum was observed for both the crystal phase and the smectic B glass phase of the DNF-40.8 system. The FMA-40.8 system exhibited a single quadrupole doublet. The In (recoil-free intensityf) versusTdata exhibited linear Debye behaviour for the solid phase over the entire temperature range. The cold smectic InfversusTdata also exhibited Debye behaviour for this system. The smectic B glass gave a Mössbauer-Debye temperature (θlc) about 23 K lower than the crystalline phase for the FMA-40.8 system and about 25 K for the DNF-40.8 system. The intermolecular contribution to the vibrational ellipsoid (εL) declined linearly with increasing temperature for both systems.

 

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