Full variational molecular orbital method: Application to the positron-molecule complexes
Journal Article
·
· International Journal of Quantum Chemistry
- Waseda Univ., Tokyo (Japan). Dept. of Chemistry
- Waseda Computational Science Consortium, Tokyo (Japan)
- Takachiho Univ., Tokyo (Japan)
Optimal Gaussian-type orbital (GTO) basis sets of positron and electron in positron-molecule complexes are proposed by using the full variational treatment of molecular orbital (FVMO) method. The analytical expression for the energy gradient with respect to parameters of positronic and electronic GTO such as the orbital exponents, the orbital centers, and the linear combination of atomic orbital (LCAO) coefficients, is derived. Wave functions obtained by the FVMO method include the effect of electronic or positronic orbital relaxation explicitly and satisfy the virial and Hellmann-Feynman theorems completely. The authors have demonstrated the optimization of each orbital exponent in various positron-atomic and anion systems, and estimated the positron affinity (PA) as the difference between their energies. The PA obtained with small basis set is in good agreement with the numerical Hartree-Fock result. They have calculated the OH{sup {minus}} and [OH{sup {minus}}; e{sup +}] species as the positron-molecular system by the FVMO method. This result shows that the positronic basis set not only becomes more diffuse but also moves toward the oxygen atom. Moreover, they have applied this method to determine both the nuclear and electronic wave functions of LiH and LiD molecules simultaneously, and obtained the isotopic effect directly.
- OSTI ID:
- 308140
- Journal Information:
- International Journal of Quantum Chemistry, Journal Name: International Journal of Quantum Chemistry Journal Issue: 3 Vol. 70; ISSN IJQCB2; ISSN 0020-7608
- Country of Publication:
- United States
- Language:
- English
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