The optical signature of 2, 6-bis((E)-2-(benzoxazol-2-yl)vinyl)naphthalene (BBVN) laser dye: a TDDFT study. (4th April 2016)

• Record Type: Journal Article
• Authors: Hammam, Essam; Ismail, Iqbal; Basahi, Jalal; Almeelbi, Talal; Hassan, Ibrahim
• Is Part Of: New journal of chemistry. Volume 40:Number 6(2016:Jun.)
• Page Start: 4911
• Page End: 4921
• Publication Date: 2016-04-04
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c5nj03523f
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : The NTO hole-particle representation of excitation demonstrates that terminal benzoxazole nuclei in BBVN promote charge displacement in absorption/emission. Abstract : The photophysical properties of the 2, 6-bis(( E )-2-(benzoxazol-2-yl)vinyl)naphthalene (BBVN) laser dye have been investigated by time-dependent density functional theory (TDDFT) using the BMK functional in the gas phase and solvents. Upon photon absorption, the dye undergoes an intense ππ* transition polarized along the long molecular axis. The natural transition orbital (NTO) representation of excitation indicates that the benzoxazole nucleus provides a room for a larger charge displacement in absorption/emission. The calculated small value of Stokes shift together with the root-mean-square distance demonstrates that the excited state (S1 ) geometry is not significantly displaced from that of the ground state (S0 ). Using a panel of solvation models (LR-PCM, cLR-PCM, and SS-PCM) we have shown that the solvent hardly has an impact on absorption but has a slight positive solvatochromic effect on fluorescence. The calculated E 0–0 energy agrees with the experimental absorption-fluorescence crossing point (AFCP). The vibronic band simulation supports the vibronic origin of the measured spectra. Owing to its large oscillator strength, short fluorescence lifetime, high photo-stability and increased rigidity in the excited state, the BBVN dye meets the necessary requirements for being a good laser dye.