Monte Carlo based electronic structure techniques: analysis and applications

✍ Scribed by J.D. Doll

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 437 KB
• Volume: 81
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(81)80264-3

✦ Synopsis

Monte CarXo based variational electronic structure techniques are exam%ned. The nature of the convergence of such met&ods, associated extrapolation methods and teclmiques for wavefuunction optimization are discussed. These techniques are i& lustrated with an application to the Hs system. Compact and accurate correlated wavefunctions for &is system are reported. 1. Introduction A common probkrn in the treatment of many-body systems is the evaluation of manydimensional integrals. Such integrals arise, for example, in the evaluation of equilibrium statistical-mechanical ensemble averages. Within this context well developed and effective numerical methods, generally known as Monte Carlo (MC) techniques [l] , are available. These techniques are especially well suited for applications involving many degrees of freedom. In the past various authors have examined the applicability of such MC techniques to the quantummechanical study of both Bose and Fermi systems, Variational approaches have been considered by Me-Millan [Z] , ~tt~gt~~ and Be&on f3] , Gibbs and Dunn f4,5], and by Ceperley et al_ f&-8] _ Non-variational approaches have been proposed by Coruoy [9], Anderson [IO] , Ceperley and Kales [8] , and by Lowther and Coldwell [I l] _ Monte Carlo based methods would appear to have several potential advantages. For example, the use of non-standard wavefunctions, and, in particular, correlated wavefunctions presents no special difficulty. Furthermore, MC techniques would appear to offer a conveuient way to synthesize extended and ftite system procedures, an important point for applications such as chemisorption which have both * This work was suppotied by the U.S. lckrpartmenr of Energy.