Browsing by Author "Gu, Fenglong"

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Franck-Condon simulation for unraveling vibronic origin in solvent enhanced absorption and fluorescence spectra of rubrene
(2017)
Hu, Ying
;
Wang, Chen-Wen
;
Zhu, Chaoyuan
;
Gu, Fenglong
;
Lin, Sheng-Hsien
Quantum chemistry calculations at the level of (TD)-DFT plus PCM solvent models are employed for analyzing potential energy surfaces and as a result two local minima with D-2, two local minima with C-2H, and one second-order transition state with D-2H group symmetry are found in both ground S-0 and excited-state S-1 potential energy surfaces. Simulated vibronic coupling distributions indicate that only second-order transition states with D-2H group symmetry are responsible for observed absorption and fluorescence spectra of rubrene and vibrational normal-motions related with atoms on the aromatic backbone are active for vibronic spectra. The Stokes shift 1120 cm(-1) (820 cm(-1)) and vibronic-band peak positions in both absorption and fluorescence spectra in non-polar benzene (polar cyclohexane) solvent are well reproduced within the conventional Franck-Condon simulation. By adding damped oscillator correction to Franck-Condon simulation, solvent enhanced vibronic-band intensities and shapes are well reproduced. Four (three) normal modes with vibration frequency around 1550 cm(-1) (1350 cm(-1)) related to ring wagging plus CC stretching and CH bend motions on the backbone are actually interpreted for solvent enhanced absorption (fluorescence) spectra of rubrene in benzene and cyclohexane solutions.
Franck-Condon simulation for unraveling vibronic origin in solvent enhanced absorption and fluorescence spectra of rubrene
(2017-01-01)
Hu, Ying
;
Wang, Chen-Wen
;
Zhu, Chaoyuan
;
Gu, Fenglong
;
Lin, Sheng-Hsien
Quantum chemistry calculations at the level of (TD)-DFT plus PCM solvent models are employed for analyzing potential energy surfaces and as a result two local minima with D-2, two local minima with C-2H, and one second-order transition state with D-2H group symmetry are found in both ground S-0 and excited-state S-1 potential energy surfaces. Simulated vibronic coupling distributions indicate that only second-order transition states with D-2H group symmetry are responsible for observed absorption and fluorescence spectra of rubrene and vibrational normal-motions related with atoms on the aromatic backbone are active for vibronic spectra. The Stokes shift 1120 cm(-1) (820 cm(-1)) and vibronic-band peak positions in both absorption and fluorescence spectra in non-polar benzene (polar cyclohexane) solvent are well reproduced within the conventional Franck-Condon simulation. By adding damped oscillator correction to Franck-Condon simulation, solvent enhanced vibronic-band intensities and shapes are well reproduced. Four (three) normal modes with vibration frequency around 1550 cm(-1) (1350 cm(-1)) related to ring wagging plus CC stretching and CH bend motions on the backbone are actually interpreted for solvent enhanced absorption (fluorescence) spectra of rubrene in benzene and cyclohexane solutions.