Unraveling the Electric Field‐Induced Dissociation Mechanism of CrO ₂ Cl ₂ : Density Functional Theory Study

Employing the density functional theory, the geometry, infrared spectra and potential energy curves of CrO 2 Cl 2 molecules are calculated at the B3LYP/6‐311G+(d,p) basis set level. After that the excitation properties of the first ten excited states of the molecules and the UV‐vis spectral characteristics under various external electric fields are studied using the TD‐SCF method with the above basis set. With the enlargement of the external electric field, the Cr─Cl bond length rises and the dipole moment reduce and then increases. Nevertheless the molecular energy and energy gap show the same trend. In aspects of charge distribution, the electropositivity of the Cl atoms decreases. When the electric field reaches F = −0.02a.u., the charge changes from positive to negative. The infrared spectra of the molecules occur varying degrees of red shift and blue shift and the UV‐vis spectra occurs blue shift. The excitation energy, excitation wavelength, and oscillator strength all change significantly. For dissociation, greater energy and external force are required. Therefore, dissociation can occur under a stronger intensity of the external electric field. Using the DET/PBEPBE/DEF2TZV method, the potential energy surfaces of the 1Cr─2Cl and 1Cr─3Cl bonds continuously decrease by applying external electric fields of intensities, thereby achieving the purpose of stepwise dissociation. It provides a theoretical basis for the protection of the environment and human health.