Orthogonality-constrained variational calculation of excited state wavefunctions and energies: a penalised-functional-based strategy

✍ Scribed by Priyatosh Dutta; S.P. Bhattacharyya

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 448 KB
• Volume: 162
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(89)85068-7

✦ Synopsis

A viable strategy is developed for the general variational calculation of excited state wavefunctions which are constrained to remain orthogonal to all the lower lying states of the same symmetry. A key element of the strategy is to employ the penalisedfunctional procedure for enforcing the relevant orthogonality constraints and a gradient-based direct method to locate the constrained minima, bypassing the problem of Hessian singularity. The workability of the algorithm is tested on some model problems.