Orientational bias of carbonyl groups in the chiral smectic C phase

Jang, Won; Park, Cheol S.; Maclennan, Joseph E.; Kim, Kyeong H.; Clark, Noel A.

doi:10.1080/00150199608223652

Cited by 57 publications

(20 citation statements)

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“…A. Sigarev et al the observed differences in the IR absorption anisotropy of the phenyl and the carbonyl bands has confirmed unambiguously the existence of biasing in the rotational orientational distribution of the "chiral" carbonyl groups with respect to the molecular long axes in ferroelectric liquid crystals (FLCs) [2][3][4][5][7][8][9][10]. This effect of biasing is considered to be a cause of the origin of the spontaneous polarization in FLCs.…”

Section: /[394]mentioning

confidence: 66%

“…The molecular arrangements in anisotropic samples of chiral smectic liquid crystals (LCs) can be studied in detail using polarized Fourier-transform infrared (FTIR) spectroscopy since the absorbance profiles of characteristic absorption bands are sensitive to the orientational distributions of their vibrational transition moments [1][2][3][4][5][6][7][8][9][10]. An IR beam of rather low intensity usually used in FTIR spectrometers enables one to examine the molecular orientations in various smectic phases and to observe the structural transformations in LC samples caused by changes in temperature or external fields non-destructively.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Structure of a Partly Deuterated Chiral Smectic Liquid Crystal Studied by Polarized FTIR Spectroscopy

Sigarev¹,

Vij²,

Fukuda³

et al. 2004

Ferroelectrics

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The molecular structure of a partly deuterated chiral smectic liquid crystal 4- in a homogeneously aligned sample is studied using polarized Fourier-transform infrared (FTIR) spectroscopy. The relative orientations of the chiral and deuterated achiral alkyl chains of molecules with respect to their long axes and some properties of the orientational distributions of the carbonyl groups are quantitatively analysed for the ferroelectric SmC * phase with a field unwound structure. The analysis is carried out in terms of the absorption anisotropy of several bands related to stretching vibrations of the phenyl C 6 H 4 fragment, the deuterated biphenyl C 12 D 8 fragment, two carbonyl groups situated in different parts of a molecule, the methylene groups CH 2 and CD 2 . It has been found that the chiral and achiral alkyl chains make substantially different angles (∼60 • and ∼36 • , respectively) with the molecular long axis. The rotational orientational distribution of the carbonyl groups about the molecular long axes has been found to have a comparatively low polar biasing.Keywords Infrared spectra of a deuterated FLC compound; biasing in a FLC compound; IR dichroism; mobility of chains in a FLC compound

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Section: /[394]mentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Molecular Structure of a Partly Deuterated Chiral Smectic Liquid Crystal Studied by Polarized FTIR Spectroscopy

Sigarev¹,

Vij²,

Fukuda³

et al. 2004

Ferroelectrics

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“…The ferroelectric liquid crystal S-(À)-2-methylbutyl 4-n-nonanoyloxybiphenyl-4 0 -carboxylate (denoted as MBOOBC or IS-2424) [16][17][18][19][20][21][22] is a interesting example of a smectogen which shows unusual behavior of sign reversal of P s , and the above mentioned simple proportionality relation between h(T) and P s (T) is not generally fulfilled. At least two explanations of this effect are possible based on the appearance of two species with opposite dipole moments [16,17] and the interplay between dipolar and quadrupolar ordering of the molecules [15].…”

Section: Introductionmentioning

confidence: 99%

Influence of dispersed aerosil particles on the collective dynamic modes in a ferroelectric liquid crystal with polarization sign reversal

Różański¹,

Thoen²

2005

Journal of Non-Crystalline Solids

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“…This equation was proposed by Jang et al 6 who obtained values of A ʈ ͑ ͒ and A Ќ ͑ ͒ by fitting it to experimental data. Several materials have been examined by means of Eq.…”

Section: ͑18b͒mentioning

confidence: 99%

Propagation of an electromagnetic wave in an absorbing anisotropic medium and infrared transmission spectroscopy of liquid crystals

Scaife

Vij

2005

The Journal of Chemical Physics

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The theory of absorbance is developed for the entire electromagnetic spectrum of radiation in a semi-infinite anisotropic medium with a second rank dielectric tensor, the elements of which are complex and frequency dependent. The theory of the absorbance A͑ , ͒ of an optically anisotropic liquid in an infrared ͑IR͒ test cell is then outlined and applied to IR transmission experiments. A formula for the dependence of A͑ , ͒, on ͑ being the angle between the electric vector and the principal optical axis͒ is derived from first principles. The formula, for radiation of angular frequency , viz, A͑ , ͒ = −log 10 ͓10 −A͑ ,0͒ cos 2 +10 −A͑ , /2͒ sin 2 ͔ is in agreement with that proposed by Jang, Park, Maclennan, Kim, and Clark ͓Ferroelectrics 180, 213 ͑1996͒ ͔ and confirms some of the work of Kocot, Wrzalik, and Vij ͓Liq. Cryst. 21, 147 ͑1996͔͒. The comments on this formula by Jang, Park, Kim, Glaser, and Clark ͓Phys. Rev. E 62, 5027 ͑2000͔͒, and by Kocot et al. are discussed. The absorbance A͑ ,0͒ and A͑ , /2͒ have been expressed in terms of the optical properties of the material and the dimensions of the cell.

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Orientational bias of carbonyl groups in the chiral smectic C phase

Cited by 57 publications

References 5 publications

Molecular Structure of a Partly Deuterated Chiral Smectic Liquid Crystal Studied by Polarized FTIR Spectroscopy

Molecular Structure of a Partly Deuterated Chiral Smectic Liquid Crystal Studied by Polarized FTIR Spectroscopy

Influence of dispersed aerosil particles on the collective dynamic modes in a ferroelectric liquid crystal with polarization sign reversal

Propagation of an electromagnetic wave in an absorbing anisotropic medium and infrared transmission spectroscopy of liquid crystals

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