Role of molecular interactions and end chain length on the photosensitivity of liquid crystalline alkyl cyanobiphenyl dimers – UV absorption-based approach through DFT calculations

Abstract

In this paper, the photosensitivity of liquid crystalline alkyl cyanobiphenyl (nCB: n = 6, 7; n is the number of carbon atoms in the alkyl chain) dimers has been presented through density functional theory (DFT) calculations. The nCB structures have been optimized using the Becke, three-parameter, Lee–Yang–Parr hybrid functional with the 6-31+G (d) basis set using the crystallographic geometry as input. The electronic structures of the dimer molecules have been computed using the optimized geometries. The spectra of the dimer molecules have been calculated by employing the DFT method. The excited states have been calculated via configuration interaction singles with the semi-empirical Hamiltonian Zerner intermediate neglect of differential overlap. The influence of molecular interactions and the end chain length on ultraviolet absorption spectral characteristics and the photosensitivity of the compounds has been discussed. These results offer a hint for the protection of various optical devices from the intense light induced damages, and to model photosensitivity.

Keywords:

• cyanobiphenyl
• dimer
• UV absorption
• photosensitivity

Acknowledgements

The financial support rendered by the CSIR, DST, New Delhi, and DAE-BRNS, Mumbai, India, is gratefully acknowledged.