In the presence of a strong electric field, novel phenomena always happen in chemical reactions, including the change of chemical reaction rate and the shifting of chemical equilibria. However, the mechanism is still unknown. This paper studies the interactions between chemical reaction systems and strong steady electric fields. Based on the theory of molecule reorientation, the modified Smoluchowski equation is expanded by the Legendre polynomials. The general expression of polarization is derived by considering the second-order nonlinear response. The nonlinear variation is also discussed through a simple isomerization reaction. The result shows that the ratio between the second-order nonlinear term and the polarization is proportional to the electric field. Meanwhile, the condition for which the result applies is also discussed.
