Abstract: Using the B3P86 method of density functional and timedependent density functional theory (TD-DFT), we calculated the excitation energies, wavelengths and oscillator strengths of acetonum molecule from the ground state to the excited states of 1—10 at the level of 6-311++G(2-df-) basis set, and investigated the effect of the external electric field on the  excitation state acetonum molecule. The results show that the excitation energy  is greatly influenced by the electric field intensity. The acetonum molecule can be easily excited and dissociated under the action of external electric field.

Key words: acetonum molecule, excited state； external electric field； spectral property