Theoretical studies on photophysical properties of fullerene and its two derivatives (C60, C60COOCH2, C60COOHCH3)

Configurations of C60 fullerene derivatives (C60COOCH2, C60COOHCH3) are optimized using B3LYP method at 6–31G* level. The calculated charge distributions by Natural Population Analysis show that the charge transfers exist between the functionalized group and parent C60. Then, the excited state properties of title species are calculated by the time-dependent density functional theory. It is shown that the fullerene derivatives make a small red shift of the absorption spectra in comparison with the C60 cage itself and the calculated electronic absorption spectra are in good agreements with their observed values.