Abstract: Using density functional theory B3P86 and time\|dependent density functional theory (TD\|DFT) method, we calculated excitation energy, transition wavelengths and oscillator strength of chiral C₁₃H₁₀N₂O₄ molecules from ground state to the excited states of 1—8 at the level of 6-311++G(2-df
-) basis sets, and studied the influence of the excited states of chiral C₁₃H₁₀N₂O₄ molecules under different external electric fields. The results show that the excitation energies Δ E of each excited state of C₁₃H₁₀N₂O₄ molecule increases with the increase of the electric field intensity, that is, the electron  isn’t easy to be excited under the limited external electric field.

Key words: excited state, external electric field, thalidomide