Abstract
Exact transformations of “N electrons inN orbitals” CASSCF structure spaces are examined that lead to modern valence bond representations, in which the total wavefunction is dominated by covalent structures built from a common product ofnonorthogonal orbitals. The resulting descriptions of the electronic structure may be compared directly with those that arise in the spin-coupled (orfull-GVB) approach. Using singlet methylene, methane and ozone as representative examples, various overlap-based and energy-based criteria are investigated for generating modern VB representations of “N inN” CASSCF wavefunctions, which we denote CASVB.
Similar content being viewed by others
References
For a review of the CASSCF method see, for example: Roos BO (1987) Adv Chem Phys 69:399
Malmqvist PÅ (1986) Int J Quant Chem 30:479
Malmqvist PÅ, Roos BO (1989) Chem Phys Lett 155:189
Thorsteinsson T (1995) Development of methods in spin-coupled theory. PhD thesis, University of Liverpool, UK
For a review of applications see, for example: Cooper DL, Gerratt J, Raimondi M (1991) Chem Revs 91:929
McWeeny R (1954) Proc R Soc Lond Ser A 223:306
Pauncz R (1979) Spin eigenfunctions. Plenum, NY
Raos G, Gerratt J, Cooper DL, Raimondi M (1993) Molec Phys 79:197
Karadakov PB, Gerratt J, Cooper DL, Raimondi M (1995) Theor Chim Acta 90:51
Paldus J (1976) In: Eyring H, Henderson DG (eds) Theoretical chemistry: advances and perspectives, Vol. 2. Academic Press, NY
Murphy RB, Messmer RP (1993) J Chem Phys 98:7958
Werner H-J, Knowles PJ (1985) J Chem Phys 82:5053
Knowles PJ, Werner H-J (1985) Chem Phys Lett 115:259
MOLPRO is a package ofab initio programs written by H-J Werner and PJ Knowles, with contributions from Almlöf J, Amos R, Elbert S, Hampel K, Meyer W, Peterson K, Pitzer R and Stone AJ
Bauschlicher CW, Taylor PR (1986) J Chem Phys 85:6510
Dunning Jr TH (1989) J Chem Phys 90:1007
Sironi M, Raimondi M, Cooper DL, Gerratt J (1987) J Chem Soc Faraday Trans 2 83:1651
Wright SC, Cooper DL, Sironi M, Raimondi M, Gerratt J (1990) J Chem Soc Perkin Trans 2, 369
Sironi M, Cooper DL, Gerratt J, Raimondi M (1990) J Am Chem Soc 112:5054
Penotti F, Cooper DL, Gerratt J, Raimondi M (1988) J Mol Struct (THEOCHEM) 169:421
Hiberty PC, Cooper DL (1988) J Mol Struct (THEOCHEM) 169:437
Pauling L (1928) Proc Natl Acad Sci USA 14:359; Pauling L (1931) J Am Chem Soc 53:1367
Raimondi M, Campion W, Karplus M (1977) Molec Phys 34:1483
Huzinaga S (1965) J Chem Phys 42:1293
Karadakov PB, Gerratt J, Raimondi M, Cooper DL (1992) J Chem Phys 97:7635
Cooper DL, Gerratt J, Raimondi M (1989) J Chem Soc Perkin Trans 2, 1187
Penotti FE, to be published; see also: Penotti FE (1993) Int J Quant Chem 46:535
Ruedenberg K, Schmidt MW, Gilbert MM, Elbert ST (1982) Chem Phys 71:41, 51, 61; Schmidt MW, Lam B, Elbert ST, Ruedenberg K (1985) Theor Chim Acta 68:69
McDouall JJW, Robb MA (1986) Chem Phys Lett 132:319
McDouall JJW, Robb MA (1987) Chem Phys Lett 142:131
Levy B (1969) Chem Phys Lett 4:17
Thouless DJ (1961) The quantum mechanics of many-body systems. Academic Press, NY
Malcolm NOJ, McDouall JJW (1994) J Comp Chem 15:1357
Cooper DL, Gerratt J, Raimondi M, Wright SC (1987) Chem Phys Lett 138:296
Malcolm NOJ, McDouall JJW (1994) J Comp Chem 15:1365
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Thorsteinsson, T., Cooper, D.L., Gerratt, J. et al. Modern valence bond representations of CASSCF wavefunctions. Theoret. Chim. Acta 93, 343–366 (1996). https://doi.org/10.1007/BF01129215
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01129215