The molecular structure optimization of Freon C₂Cl₂F₄ (F-114) and infrared (IR) spectra were obtained by density functional theory (B3LYP/6-31G++(d,p)) calculations,and the calculated IR spectra are in good agreement with experimental results.Additionally,the excited state and low ionic excited states of Freon C₂Cl₂F₄ were calculated by performing ab initio calculations with CIS method.The obtained bond length,bond angle and dihedral angle for the low molecular excited states are compared and analyzed.Meanwhile,UV-Vis spectra and molecular frontier orbits for the C₂Cl₂F₄ are obtained.Finally,the photodissociation dynamics of the low ionic excited states of the ionic cation C₂Cl₂F₄⁺ are discussed.