Study on the Change Rule of the First Ionization Potential for Halohydrocarbon

It can be expressed as following equation for the change rule of the first ionization potential （Ip） of halohydrocarbon RX:Ip（eV） = 3.3380 + 0.7344Ep（X）+ 2.74224 （1/（a_x ））q_x - 1 .4302PEIwhere Ep （X） and a_x are the ionization potential of outermost P electron and atomic polarizability for halogen atom respectively, q_x is the partial charge on halogen atom X in halohydrocarbon molecule RX, and PEI is the polarizability effect index of alkyl group in the molecule RX. The result shown there were good agreement between the ionization potential values estimated by above expression and the experiment values for the investigated halohydrocarbon.