Computational prediction of relative group polarizabilities

Earlier work has shown that molecular polarizabilities correlate well with the quantity V/ I S ,ave , where V is the volume of the molecule and I S ,ave is the average value of the local ionization energy on its surface. We now extend this to group polarizabilities; we computed V/ I S ,ave for four common chemical groups (NO 2 , CH 3 , NH 2 , and OH) in a variety of molecules. The transferabilities of I S ,ave , V , and V/ I S ,ave are examined, as well as the correlation between V/ I S ,ave and literature polarizabilities of CH 3 , NH 2 , and OH. This permits the value for NO 2 to be predicted (α = 2.77 Å 3 ). The dependence of I S ,ave , and therefore V/ I S ,ave , upon the remainder of the molecule is discussed. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003