Linear expansions of correlated functions: Variational Monte Carlo case study

The relative performance of trial wave functions expressed as linear combin ation of correlated exponentials has been tested on a variety of systems. T he results are compared against other correlated functions commonly used in the literature to assess the capabilities of the proposed ansatz. A possib le departure from the simple exponential functional form used in previous w orks is discussed, along with its advantages and drawbacks. We also discuss how to implement an efficient optimization procedure for this correlated b asis set. (C) 1999 John Wiley & Sons, Inc. Int J Quant Chem 73: 23-33, 1999 .