Effects of external electric fields on molecular properties of nitrogen/tetrafluoromethane complex: A density functional theory study

Nitrogen/tetrafluoromethane (N2/CF4) has attracted wide attention for its reliable dielectric performance and potential to be utilized as a coolant and insulator of power apparatus. Several studies have investigated the basic properties of N2/CF4, but dielectric responses of such a mixture under extreme electric fields are not fully understood, primarily on a molecular level. Here, we modeled the N2/CF4 complex and calculated the molecular properties under different external electric fields through computational quantum chemistry methods. Results suggest that the electric-field-induced polarization can be apparently observed in both positive and negative direction cases; the deformed electronic structure leads to an increased dipole moment and a narrowed energy gap. In addition, the molecular vibrational modes are sensitive to external electric fields, resulting in the splitting and shifting of IR spectra. Moreover, the external electric field also affects the excited state properties of N2/CF4, and the emerged absorption peaks under extreme electric fields were analyzed in detail. These findings provide a better understanding of the N2/CF4 properties under external electric fields and lay a foundation for designing the electrical insulation systems of the power apparatus.