Local reactivity indices of free radicals: <i>Ab initio</i> Hartree-Fock and Kohn-Sham density functional calculations

Abstract

The local reactivity indices such as condensed fukui function (f_A^o) , unpaired spin population (S_A) and free valency (F_A) of a number of free radicals have been calculated by <i>ab initio</i> HF and density functional (B3LYP) methods using different schemes of population analysis and basis sets. Irrespective of the choice of the variants in the methods of calculation the three indices predict identical site for a free radical attack in most cases. However, since the B3LYP wave functions describe almost pure spin states, they are preferable to the

<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:fd1596850-identity-h;color:black;mso-ansi-language:="" en-in;mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">UHF wave functions which are appreciably spin contaminated in many cases. The stereoselectivity of a few simple reactions has been discussed using these indices. Of the three quantities, the free valency is found to be most satisfactory.</span>