Raman spectroscopy study and density functional theory calculations of the nematic liquid crystal 4-n-pentyl-4′-cyanobiphenyl under an electric field

Vibrational spectra of 4-n-pentyl-4′-cyanobiphenyl in a liquid crystalline cell have been studied by means of micro-Raman spectroscopy when an electric field was applied up to ∼104 V/cm. To further elucidate the intramolecular changes upon the presence of the electric field, density functional theory calculations have been applied to 5CB molecule under various electric field strengths. The inter-ring C-C bond distance connecting two phenyl rings was found to be most affected along with the variance of the inter-ring torsional angle only by the electric field as high as ∼5 × 107 V/cm.