NEW EMPIRICAL-METHOD TO CALCULATE AVERAGE MOLECULAR POLARIZABILITIES

A new empirical method is presented for the calculation of average molecular polarizabilities. It is based on the square of a sum of atomic hybrid components (ahc), namely, α(ahc) = (4/N)[ΣAΤA]2(A3), where the summation proceeds over all atoms A = 1,2,3,…, and N is the total number of electrons in the molecule. Only one parameter △A is required for an atom in a particular hybrid configuration. Calculated average molecular polarizabilities of approximately 240 molecules containing H,C,N,O,S,F,CI,Br, and 1 yield results that are competitive with the method of summation of atomic and bond polarizabilities, and they are in excellent agreement with experimental results. In addition, the atomic polarizability αA = (4/NA) ΤA2 calculated for each hybrid state provides an estimate of atomic size with ρA = 1.05√34 √α0αA which compares well to the van der Waals radius of each atom. © 1979, American Chemical Society. All rights reserved.