Structure and electronic absorption spectra of nematogenic alkoxycinnamic acids – a comparative study based on semiempirical and DFT methods

Abstract

Structure of nematogenic p-n-Alkoxy cinnamic acids (nOCAC) with various alkyl chain carbon atoms (n = 2, 4, 6, 8) has been optimized using density functional B3LYP with 6-31+G (d) basis set using crystallographic geometry as input. Using the optimized geometry, electronic structure of the molecules has been evaluated using the semiempirical methods and DFT calculations. Molecular charge distribution and phase stability of these systems have been analyzed based on Mulliken and Löwdin population analysis. The electronic absorption spectra of nOCAC molecules have been simulated by employing DFT method, semiempirical CNDO/S and INDO/S parameterizations. Two types of calculations have been performed for model systems containing single and double molecules of nOCAC. UV-Visible spectra have been calculated for all single molecules. The UV stability of the molecules has been discussed in light of the electronic transition oscillator strength (f). The dimer complexes of higher homologues (n = 6, 8) have also been reported to enable the comparison between single and double molecules.

Quantum mechanical studies of p-azoxyanisole and identification of its electro-optic activity

“…1 It is thought that one of the elements affecting the geometry of the molecule causes molecular ordering to occur in the LC phase, which is an intriguing topic. 2,3 Physical characteristics such as anisotropy are closely related to the phase structure which results from a minimal interaction between the molecular structure on the inside and the energy of molecular interactions. 4,5 A statistical perspective on thermodynamic parameters can greatly aid in understanding the delicate balance between energy and entropy.…”

Effect of substituent on UV–visible absorption and photostability of liquid crystals: DFT study

“…Of particular importance in this sense, methods based on time-dependent density functional theory (DFT) provide very accurate results. [7,8] Such approaches allow for the calculation of electronic transitions between the ground state and the different excited states, which gives the energies of the corresponding radiations. Each transition can be enlarged with a Gaussian shape due to the several factors such as thermal excitement, natural line width, etc.…”

Effect of Molecular Interactions and Homologue Number on UV Absorption Spectra of Liquid Crystalline Alkyl Cyanobiphenyl Dimers: DFT Calculations

“…

The ultraviolet (UV) absorption spectra of the liquid crystalline dimer complexes of 4,5 where n is the number of carbon atoms in the alkyl chain) have been presented. The nCB structures have been optimized using the density functional Becke3-Lee-Yang-Parr (B3LYP) hybrid functional with 6-31+G (d) basis set using the crystallographic geometry as input.

…”