Journal ArticleDOI
Pre-resonance Raman studies of some mesogens-TB4A, TB7A and TB10A
TLDR
In this article, the anomalous intensity enhancement mechanism was explained by invoking an interference effect between a weak dipole-forbidden excited state and a nearby strong electronic level via vibrational modes.Abstract:
Pre-resonance Raman spectra of certain liquid crystalline compounds, TB4A, TB7A and TB10A, are reported. The anomaly observed in the pre-resonance Raman spectra in the three compounds was initially explained by the Albrecht-Hutley Model, but its failure leads us to explain the anomalous intensity enhancement mechanism by invoking an interference effect between a weak dipole-forbidden excited state and a nearby strong electronic level via vibrational modes. The presence of a 21Ag dipole-forbidden excited state in TB4A and TB10A is deduced after an elaborate discussion of their centro-symmetric structure. The structural difference of TB7A in comparison with TB4A and TB10A is also discussed by taking their X-ray data into consideration.read more
Citations
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Journal ArticleDOI
Differing applications of Raman scattering to liquid crystals
P. Etchegoin,John M. Seddon +1 more
TL;DR: In this paper, an overview of the different possibilities offered by Raman scattering in the study of liquid crystals is given, together with a few experimental examples of the least studied phenomena.
Journal ArticleDOI
Virus shaped gold nanoparticles with tunable near infrared plasmon as SERS substrates
S.G. Jiji,K.G. Gopchandran +1 more
TL;DR: In this paper, a facile seed mediated strategy for the synthesis of virus shaped gold nanoparticles (AuNPs) with plasmon band tunable from 650 to 1200 nm is reported.
Journal ArticleDOI
Linear Low Density Polyethylene-Thermotropic Liquid Crystal Composite Substrate for High-Frequency Devices: Dielectric Characterization
TL;DR: In this paper, composites of linear low-density polyethylene with thermotropic liquid crystals as inclusions with three different weight fractions were synthesized and the dielectric characterizations of the composites in X band frequencies were studied to assess their applicability as substrates for microwave devices.
References
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Journal ArticleDOI
On the Theory of Raman Intensities
TL;DR: In this article, the Herzberg-Teller development for vibronic transition moments is introduced into the Kramers-Heisenberg dispersion equation and an equation for the polarizability components is obtained which leads directly to the Raman selection rules.
Journal ArticleDOI
Time‐dependent theory of Raman scattering
Soo-Y. Lee,Eric J. Heller +1 more
TL;DR: In this paper, a time-dependent model of vibrational Raman scattering in the weak field limit is presented, where the wave packet, given by the initial vibrational wave function times the transition dipole, hardly moves on the excited surface when the excitation frequency is far from resonance.
Journal ArticleDOI
Über die Streuung von Strahlung durch Atome
H. A. Kramers,W. Heisenberg +1 more
TL;DR: In this article, a wellentheoretische analyse der streuenden Wirkung des Atoms an der Hand des Korrespondenzprinzips m ungezwungener und scheinbar eindeutiger Weise durchfuhren last.
Journal ArticleDOI
A low-lying weak transition in the polyene α,ω-diphenyloctatetraene
Bruce S. Hudson,Bryan E. Kohler +1 more
TL;DR: In this paper, an excited singlet state at lower energy than the 1B1u state responsible for the strong absorption at 4100 A was found and the presence of this state rationalized a number of distinctive characteristics of polyene spectra which had previously been explained on the basis of "Franck-Condon forbiddeness".
Journal ArticleDOI
Polyene spectroscopy: The lowest energy excited singlet state of diphenyloctatetraene and other linear polyenes
Bruce S. Hudson,Bryan E. Kohler +1 more
TL;DR: In this paper, a review of the available information on diphenyl polyenes is presented and a correlation of the oscillator strength of the fluorescence transition as deduced from the emission lifetime with the separation of the low energy excited states for a number of polyenes are noted.