Abstract:

Using density functional B3P86 and timedependent density functional theory (TD-DFT) method, the author calculated wavelengths, oscillator strengths and excitation energy of chiral ibuprofen molecules from ground state to the excited states of 1—10 at the 6-311++g(d,p) basis sets, and studied the influence of the excited states of chiral ibuprofen molecules under different external electric fields. The results show that the HOMO-LUMO energy gaps
 are gradually weakened, and the excitation energies decrease sharply with the increase of the external electric field intensity. The molecules can be easily excited and dissociated under the action of external electric field.

Key words: time-dependent density functional theory (TD-DFT), chiral ibuprofen, excited state, electric field