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This article studies the density functional theory (DFT) and experimentally measured Raman spectrum of 5O.14 monomeric liquid crystalline compound. Raman spectroscopy in liquid crystal (LC) is very sensitive to temperature and with the variation of temperature every bond in the molecule shows different Raman peaks. Some important changes in the peaks were also noticed in different phases with the change in temperature. These changes occurred basically due to the changes in the molecular orientation with varying temperature. The structural and dynamics changes of the LC undergoing phase transitions have been analysed from the investigations of peak positions and linewidths. Finally, the results obtained from experimental and DFT generated Raman spectra confirm some interesting features to understand the behaviours of 5O.14 LC. [ABSTRACT FROM AUTHOR]

The interactions between liquid crystal (LC) 4´-pentyl-4-biphenylcarbonitrile and protein bovine serum albumin are investigated to develop an LC-based biosensor. Various techniques, such as polarising optical microscopy, Raman spectroscopy, and molecular docking method, are used for analysing these interactions. The change in the alignment of LC molecules in the presence of bovine serum albumin results in the director configuration transition. This transfiguration of the director of LC molecules, when it undergoes a change from radial to bipolar configuration, confirms the detection of albumins under polarising optical microscopy. The limit of detection is also determined from this study. The Raman spectra are deconvoluted to calculate the spectral parameters, namely peak position, linewidth, and integrated intensity. The variation of these parameters with concentration and temperature is discussed, pertaining to the changes in orientational ordering and inter/intramolecular interactions. The active binding sites, active residues and binding energy are calculated by molecular docking analysis. The active binding residues of albumins involved in the docking with liquid crystal are further confirmed using Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Temperature-dependent micro-Raman study of C-H in-plane bending mode of aromatic rings, C-N and C=N stretching of linking group (-C(H)=N) and C=C stretching of rings of pure and silver nanoparticles dispersed (0.5% and 1% by weight) Schiff's base liquid crystal (LC) compound, N-(4-n-heptyloxybenzylidene)-4'-n-butylaniline (7O.4) in 500-2250 cm−1 region has been done. The change in Raman spectral parameters (peak position and linewidth) at crystal-smecticG (K-smG) and smecticG-smecticC (smG-smC) gives the evidence of charge shift at phase transition which is associated with changes in orientation and vibrational freedom of the molecules. The peak position of the Raman bands shows blue shift for 0.5 wt% dispersed sample, whereas it shows red shift for 1 wt% dispersed sample. The blue and red shifts of the Raman bands indicate an increase and decrease in the charge density, respectively. The optimised structure and theoretical room temperature Raman spectra of 7O.4 were obtained using density functional theory. The vibrational assignment using potential energy distribution is reported using vibrational energy distribution analysis (VEDA). [ABSTRACT FROM AUTHOR]