Light scattering study near the crystal to nematic transition in para-azoxyanisole (PAA)

Z. Iqbal; F. J. Owens; C. W. Christoe

doi:10.1016/0009-2614(79)87127-4

Light scattering study near the crystal to nematic transition in para-azoxyanisole (PAA)

Z. Iqbal, F. J. Owens, C. W. Christoe

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Abstract

Low frequency Raman and quasi-elastic scattering from para-azoyanisole (PAA) has been investigated between 5 and 100 cm^-1, near the crystal to nematic phase transition at 117°C. A central quasi-elastic wing, qualitatively shown to be associated with a Debye-like process is observed at 114°C and above. The intensity of the Raman lines determined from a computer fit of the lattice mode Raman spectra to lorentzian expressions show a relatively sharp decrease in the vicinity of T_c, indicative of a first order transition. No indication of a propagating soft mode near T_c was found. Raman peaks at 13, 34, 54 ± cm^-1 superimposed on the strong quasi-elastic scattering were observed in the nematic liquid crystal phase.

Original language	English (US)
Pages (from-to)	157-159
Number of pages	3
Journal	Chemical Physics Letters
Volume	67
Issue number	1
DOIs	https://doi.org/10.1016/0009-2614(79)87127-4
State	Published - Nov 1 1979
Externally published	Yes

All Science Journal Classification (ASJC) codes

General Physics and Astronomy
Physical and Theoretical Chemistry

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10.1016/0009-2614(79)87127-4

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title = "Light scattering study near the crystal to nematic transition in para-azoxyanisole (PAA)",

abstract = "Low frequency Raman and quasi-elastic scattering from para-azoyanisole (PAA) has been investigated between 5 and 100 cm-1, near the crystal to nematic phase transition at 117°C. A central quasi-elastic wing, qualitatively shown to be associated with a Debye-like process is observed at 114°C and above. The intensity of the Raman lines determined from a computer fit of the lattice mode Raman spectra to lorentzian expressions show a relatively sharp decrease in the vicinity of Tc, indicative of a first order transition. No indication of a propagating soft mode near Tc was found. Raman peaks at 13, 34, 54 ± cm-1 superimposed on the strong quasi-elastic scattering were observed in the nematic liquid crystal phase.",

author = "Z. Iqbal and Owens, {F. J.} and Christoe, {C. W.}",

year = "1979",

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doi = "10.1016/0009-2614(79)87127-4",

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T1 - Light scattering study near the crystal to nematic transition in para-azoxyanisole (PAA)

AU - Iqbal, Z.

AU - Owens, F. J.

AU - Christoe, C. W.

PY - 1979/11/1

Y1 - 1979/11/1

N2 - Low frequency Raman and quasi-elastic scattering from para-azoyanisole (PAA) has been investigated between 5 and 100 cm-1, near the crystal to nematic phase transition at 117°C. A central quasi-elastic wing, qualitatively shown to be associated with a Debye-like process is observed at 114°C and above. The intensity of the Raman lines determined from a computer fit of the lattice mode Raman spectra to lorentzian expressions show a relatively sharp decrease in the vicinity of Tc, indicative of a first order transition. No indication of a propagating soft mode near Tc was found. Raman peaks at 13, 34, 54 ± cm-1 superimposed on the strong quasi-elastic scattering were observed in the nematic liquid crystal phase.

AB - Low frequency Raman and quasi-elastic scattering from para-azoyanisole (PAA) has been investigated between 5 and 100 cm-1, near the crystal to nematic phase transition at 117°C. A central quasi-elastic wing, qualitatively shown to be associated with a Debye-like process is observed at 114°C and above. The intensity of the Raman lines determined from a computer fit of the lattice mode Raman spectra to lorentzian expressions show a relatively sharp decrease in the vicinity of Tc, indicative of a first order transition. No indication of a propagating soft mode near Tc was found. Raman peaks at 13, 34, 54 ± cm-1 superimposed on the strong quasi-elastic scattering were observed in the nematic liquid crystal phase.

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JO - Chemical Physics Letters

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Light scattering study near the crystal to nematic transition in para-azoxyanisole (PAA)

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