偶氮苯及其衍生物吸收光谱的密度泛函理论研究

he ground-state structures and vertical excited energies of cis-/trans-azobenzene in various environments(in gas phase or normal organic solvents) have been explored by means of (time-dependent) density functional theory calculations with use of nine types of density functionals and eleven types of basis sets in different size. The TD-wB97XD/6-311+G(2d,p)//M06/6-31++G(d,p) prediction appeared to be the best in reproducing experimental data. At this very level of theory, the vertical excited energies of a total of 173 azobenzene derivatives in different environments have thus been computed and compared with the available experimental data. For the full set of absorption wavelengths concerned, the currently recommended TD-wB97XD/6-311+G(2d,p)//M06/6-31++G(d,p) prediction gives a mean unsigned error (MSE) of -3.4 nm and a mean absolute error (MAE) within 15.5 nm, and the linear correlation between the experimental and theoretical data gives a R2 value of 0.88. This method also correctly predicts the observed cis-trans shifts in the characteristic absorptions of those azobenzene derivatives.