Use of CI Methods for the Study of Molecular Dissociation Processes in Various Electronic States
- 159 Downloads
The adequate description of bond-breaking processes is a difficult problem since it requires very good correlated wavefunctions to account for the generally quite large difference in correlation energy between the combined system and the individual fragments. The situation is especially critical if multiple bonds are broken as in N2, for example, for which the single-configuration Hartree-Fock treatment yields only a dissociation energy of De= 5.18 eV , i.e 4.72 eV below the experimental result . But even in systems containing only a single bond such as F2 the use of correlated wavefunctions is essential since it is well-known that this molecule is not even found to be bound with respect to two F atoms in the Hartree-Fock approximation. And finally it is also obvious that extremely weak bonds like van der Waals interactions can only be described by methods going beyond the single-configuration approach.
KeywordsPotential Energy Surface Dissociation Energy Dissociation Limit Calculated Potential Energy Dissociation Path
Unable to display preview. Download preview PDF.
- 5.J. Römelt, S.D. Peyerimhoff and R.J. Buenker, Chem. Phys, in pressGoogle Scholar
- 6.J. Römelt, Ph. D. thesis, Bonn (1977)Google Scholar
- 9.S.D. Peyerimhoff and R.J. Buenker, in “The New World of Quantum Chemistry”, eds. B. Pullmann and R. Parr, D. Reidel Publ. Co., Dordrecht, Holland (1976)Google Scholar
- 11a.See also H.F. Schaefer “The Electronic Structure of Atoms and Molecules”, Addison-Wesley, Reading, Mass. (1972)Google Scholar
- 13.See for example, M.B. Robin in “Higher Excited States of Polyatomic Molecules”, Academic Press, New York/London (1974), Vol. 1;Google Scholar
- 13a.K.H. Becker and K.H. Welge, Z. Naturforsch. A 17, 676 (1962)Google Scholar
- 13b.K.H. Becker and K.H. Welge, Z. Naturforsch. A 18, 600 (1963)Google Scholar
- 13d.J. Masanet, A. Gilles and C. Vermeil, J. Photochem. 3, 417 (1974/75).Google Scholar
- 18.R.S. Mulliken, Int. J. Quantum Chem. 5S, 83 (1971)Google Scholar
- 20.Results of this laboratoryGoogle Scholar