title: Triphenylamine-Based Fluorescent Styryl Dyes: DFT, TD-DFT and Non-Linear Optical Property Study.
abstract: The electronic structures and spectroscopic properties of triphenylamine-based monostyryl and bis(styryl) dyes were studied using quantum chemical methods. The ground-state geometries of these dyes were optimized using the density functional theory (DFT) method. The lowest singlet excited state was optimized using time-dependent density functional theory (TD-DFT). The absorption was also calculated using the ground-state geometries. All the calculations were carried out in the gas phase and in solvent. The results indicate that the absorption maxima calculated using the TD-DFT are in good agreement with those obtained experimentally. These dyes possess a large second-order non-linear property and this is mainly due to the strong donor-π-acceptor conjugation which is attributed to the excited state intramolecular charge transfer (ICT). There is a relationship between the hardness and first hyperpolarizability and second hyperpolarizability of mono- and bis(styryl) dyes. The efficiency of the intersystem crossing process can be improved by reducing the energy gap between the singlet and triplet excited states.
authors.affiliation: Department of Dyestuff Technology, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, MH, 400019, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Katariya
authors.affiliation: Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80837, Mauritius.
authors.forename: Lydia
authors.initials: L
authors.lastname: Rhyman
authors.affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia.
authors.forename: Ibrahim A
authors.initials: IA
authors.lastname: Alswaidan
authors.affiliation: Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80837, Mauritius. ramchemi@intnet.mu.|Department of Chemistry, College of Science Engineering and Technology, University of South Africa, P.O. Box 392, Pretoria, 0003, South Africa. ramchemi@intnet.mu.
authors.forename: Ponnadurai
authors.initials: P
authors.lastname: Ramasami
authors.affiliation: Department of Dyestuff Technology, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, MH, 400019, India. n.sekar@ictmumbai.edu.in.
authors.forename: Nagaiyan
authors.initials: N
authors.lastname: Sekar
keywords: DFT; Hardness; Hyperpolarizability; TD-DFT; Triphenylamine-based dyes