Nonsingular two/one-component relativistic Hamiltonians accurate through arbitrary high order in α2
✍ Scribed by Maria Barysz; Andrzej J. Sadlej; Jaap G. Snijders
- Book ID
- 101249855
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 214 KB
- Volume
- 65
- Category
- Article
- ISSN
- 0020-7608
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✦ Synopsis
A series of nonsingular two-component relativistic Hamiltonians is derived from the Dirac Hamiltonian by first performing the free-particle Foldy᎐Wouthuysen transformation and then a block-diagonalizing transformation. The latter is defined in terms of operators which can be determined iteratively through arbitrary order in ␣, leading to transformed Hamiltonians with the two-component block accurate through ␣ 2 k , k s 1, 2, 3, . . . . These Hamiltonians give relativistic energies which differ from Dirac's energies only in terms higher than ␣ 2 k . Their relation to other Ž nonsingular methods of relativistic quantum chemistry the Douglas᎐Kroll method, the . regular Hamiltonian schemes is discussed. By removing the spin-dependent operators, the derived Hamiltonians can be written in spin-free one-component form. The computational effort involved is essentially the same as in the case of the Douglas᎐Kroll scheme and amounts to relatively easy modification of the core Hamiltonian.