DESIGN OF AN EXCHANGE FUNCTIONAL WITH CORRECT ASYMPTOTICS

Knowledge of asymptotic conditions on exchange allows for a better des ign of exchange energy expressions in density functional theory. By wo rking inside an exchange-only framework, the fulfillment of such condi tions by some of the most widely used exchange functionals is discusse d. In turn, we propose a model expression which partially meets the en ergetics and asymptotics of both the exchange energy density and poten tial. Improvement upon the local spin density approximation without th e use of generalized gradient corrections is also presented. Hartree-F ock orbitals are employed to build electron densities. (C) 1997 John W iley & Sons, Inc.