DFT Study on Molecular Spectra and Excited State of 7-(4-(3,6-dinitro-carbazole-9-yl)styryl)Coumarin

The full geometry optimization of 7-(4-(3,6-dinitro-carbazole-9-yl)styryl)coumarin was performed using Density Functional Theory(DFT)method at B3LYP/6-311G(d,p)level of theory.Based on the optimized configuration the IR and Raman spectra of this molecule were obtained by the frequency analysis,and the peak position of the IR and Raman spectra were analysed by Gaussian View program.The HOMO-LUMO energy gap was gained as 2.150eV simultaneously.The ten lowest allowable singlet excited states were studied by Time-dependent Density Functional Theory(TDDFT)method.The formation ofπ-delocalized bond was observed through the frontier molecular orbital of 7-(4(3,6-dinitro-carbazole-9-yl)styryl)coumarin.The results showed that 7-(4-(3,6-dinitrocarbazole-9-yl)styryl)coumarin is a well organic semiconductior material and has perfect luminescence properties.