کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9575494 | 1504350 | 2005 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Mapping the many-electron generalised spin-exchange Hamiltonian to accurate post-HF calculations
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
After some remarks about the theoretical foundations of the many-electron Heisenberg-Dirac spin Hamiltonian, we have investigated the transferability of the two-body spin-exchange parameter of this model mapping accurate post-Hartree-Fock results obtained for H2, H3 and H4 systems with the analytical solutions of the corresponding spin Hamiltonian. Highly symmetric structures, described by only one independent spin-exchange parameter, and less symmetric cases, described by two or three spin-exchange parameters have been analyzed. The generalized many-body Heisenberg-Dirac Hamiltonian is found to be suited to reproduce the ab initio values for Hn clusters (n = 2, 3, 4) when internuclear distances are larger that 3 Ã
, i.e., beyond the bonding region. Concerning the transferability of the two-electron spin exchange parameter (JH2) in this internuclear distance region, particular attention should be paid to the characteristics of the systems analyzed and to their relationship with the parent molecule (here H2), as underlined by the results obtained for H4 square planar system and linear H3 system.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 309, Issues 2â3, 14 March 2005, Pages 133-141
Journal: Chemical Physics - Volume 309, Issues 2â3, 14 March 2005, Pages 133-141
نویسندگان
Ilaria Ciofini, Carlo Adamo, Vincenzo Barone, Gaston Berthier, André Rassat,