Exploration of a 7.O4O.7 dimeric liquid crystal using temperature-dependent Raman spectroscopy and comparison with...

Area of Science:

• Materials Science
• Physical Chemistry
• Spectroscopy

Background:

• Analysis of the 7.O4O.7 dimeric liquid crystal, exhibiting SmF and SmA phases.
• Investigation of temperature-dependent Raman spectral characteristics: peak position, integral intensity, and FWHM.
• Exploration of molecular orientational and vibrational freedoms in relation to temperature.

Purpose of the Study:

• To analyze temperature-dependent Raman spectra of the 7.O4O.7 dimeric liquid crystal.
• To investigate charge displacement during liquid crystal phase transitions.
• To validate theoretical calculations against experimental data.

Main Methods:

• Experimental Raman spectroscopy using Horiba Lab RAM HR Evolution.
• Theoretical calculations using Gaussian 09 with B3LYP functional and 6-31G (d,p) basis set.
• Analysis and visualization using Gauss View 06 and VEDA 4 for vibrational mode assignment.

Main Results:

• Observed variations in Raman peak position, integral intensity, and FWHM with temperature.
• Evidence of charge displacement during SmF and SmA phase transitions.
• Precise agreement between experimental and DFT-calculated Raman spectra at room temperature.

Conclusions:

• Raman spectral changes provide insights into liquid crystal phase transitions.
• DFT calculations are validated for analyzing the 7.O4O.7 dimeric liquid crystal.
• Vibrational mode assignment confirmed through PED and VEDA calculations.