On the calculation of atomization energies of organic molecules in the Xα local spin density approximation

The atomization energies of selected alkanes, alkyl radicals, and amines are deduced from Xα local spin density calculations of E, the total energy of a molecule in its potential minimum. Both the exchange-correlation energy, , and itself obey, in a first approximation, simple atom-by-atom additivity rules. The appropriate α's for use in Xα(LSD) calculations of organic molecules thus appear as weighted averages and depend on the particular composition of each molecule. The at least approximate validity of this averaging procedure is illustrated by the accuracy of calculated atomization energies.