Spectrum and Physical Properties of C70 Under the External Electric Field

Abstract

Fullerene C70 has a broad application prospect. It is of great significance for investigating the properties of fullerene C70 under the external electric field. The dipole moment, energy gap and infrared spectrum of fullerene C70 molecule under external electric field (0–0.040 atomic units) are studied with density functional theory at B3PW91/3-21G level. The dipole moment increases almost linearly from 0.005 to 65.005 Debye and the energy gap decreases continuously. The effect of external electric field on the infrared spectrum is great and it can be found that certain vibrational mode become active due to the symmetry reduction due to the external electric field. Meanwhile, the ultraviolet–visible absorption spectra, the excitation wavelength, the excitation energy, and oscillator strength of first fourteen excited states of fullerene C70 under the external electric field are also studied with the time-dependent density functional theory at B3PW91/3-21G level. It is found that the absorption peak of fullerene C70 occurs red shift from 504.78 to 736.39 nm. The excitation energy decreases rapidly and the excitation wavelength increases a lot with the external electric field. The results can offer an important reference to use external electric field to tune the properties of fullerene C70.