On the performance of approximate spin–orbit Hamiltonians in light conjugated molecules: the fine-structure splitting of HC6H+, NC5H
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- 作者：Tatchen ; Jö ; rg ; Marian ; Christel Maria
- 刊名：Chemical Physics Letters
- 出版年：1999
- 出版时间：November 5, 1999
- 年：1999
- 卷：313
- 期：1-2
- 页码：351-357
- 全文大小：130 K
文摘
Spin–orbit calculations have been performed on the carbon-rich radical cations HC6H+, NC5H+, and NC4N+ using the full one-and two-electron no-pair spin–orbit Hamiltonian and more approximate approaches. It is found that the full operator can be replaced by an effective one-electron mean-field spin–orbit Hamiltonian almost without loss of accuracy. An analysis of the approximations reveals that multi-center integrals are large, but one- and two-electron terms tend to cancel. The one-center spin–orbit mean-field approach yields fine-structure splittings within 5 % of the full results and thus appears to be a favorable means to reliably predict rates of spin-forbidden processes in organic molecules at low cost.