Assessment of the qualities of some electronic wave functions by a modified local-energy method

The validity and desirability of using different weighting factors with the modified local-energy method which was developed previously (Rourke and Stewart 1967) is indicated.The possible advantages of this method over the variation method are discussed and a search is made among the more common types of wave function for those which are of sufficiently high quality for use with this modified local-energy method. It is shown that the more common wave functions are unlikely to reach this standard except when electron–electron correlation effects are very low.A regression curve for the accuracy of energies by the present method and the accuracy by the variation method is given. It shows that the results from the variation method are always likely to be more accurate than those from the modified local-energy method when the same wave functions are used.Since one advantage of a local-energy method is the ease with which the type of wave function can be changed, a more systematic search for suitable wave functions by optimizing the analytical expression as well as variable parameters appears worthwhile.