CONVERGENCE ACCELERATOR APPROACH FOR THE HIGH-PRECISION EVALUATION OF3-ELECTRON CORRELATED INTEGRALS

The standard series expansion that has long been employed to evaluate one-center correlated three-electron integrals is converted into a dif ferent form. The alternative expression obtained allows convergence ac celerator techniques to be directly applied in a very effective manner . The resulting expansion is found to be numerically stable, in contra st to the series obtained when convergence accelerator techniques are applied to the standard expansion. Using this approach, the increase i n computational speed is found to be very significant for the most slo wly converging integrals. Some representative values are presented for a number of three-electron correlated integrals calculated using the method suggested herein.