| Автор | J A Aramburu |
| Автор | M Moreno |
| Автор | M T Barriuso |
| Дата выпуска | 1992-11-16 |
| dc.description | The dependence of the optical and spin-Hamiltonian parameters of NiF<sub>6</sub><sup>5-</sup> and NiF<sub>4</sub><sup>3-</sup> D<sub>4h</sub> units, with a b<sub>1g</sub>* ( approximately x<sup>2</sup>-y<sup>2</sup>) unpaired electron, upon the equatorial (R<sub>eq</sub>) and axial (R<sub>ax</sub>) Ni<sup>+</sup>-F<sup>-</sup> distances has been studied through multiple-scattering X alpha and self-consistent charge extended Huckel methods. Both methods lead to the following main conclusions: (i) A charge-transfer transition like e<sub>u</sub>( pi + sigma ,eq) to b<sub>1g</sub>*( approximately x<sup>2</sup>-y<sup>2</sup>) (termed E<sub>u</sub>) is more sensitive than a crystal-field one like b<sub>2g</sub>* ( approximately xy) to b<sub>1g</sub>*( Delta <sub>1</sub>) or e<sub>g</sub>* to b<sub>1g</sub>*( Delta <sub>2</sub>) to variations in R<sub>eq</sub>. The change experienced by E<sub>u</sub> mainly reflects that of V<sub>el</sub>(M)-V<sub>el</sub>(L), where V<sub>el</sub>(M) and V<sub>el</sub>(L) are the electrostatic potentials experienced by an electron placed on metal and ligands, respectively, (ii) As regards the unpaired spin densities onto n<sub>L</sub>p and n<sub>L</sub>s ligand valence orbitals (termed f<sub>sigma </sub> and f<sub>s</sub> respectively), it is found that f<sub>sigma </sub>>>f<sub>s</sub> but f<sub>s</sub> is much more sensitive than f<sub>sigma </sub> to changes in R<sub>eq</sub>. The microscopic origin of this relevant fact is explained in detail. (iii) The removal of axial ligands, keeping R<sub>eq</sub> constant, induces a decrease of E<sub>u</sub> as a result of the diminution of the electrostatic repulsion, V<sub>el</sub> (M), and produces a slight increase of Delta <sub>1</sub> and a more important one of Delta <sub>2</sub>. (iv) The dependence of <sub>g</sub>//-g<sub>0</sub> and g<sub>perpendicular to </sub>-g<sub>0</sub> on R<sub>eq</sub> essentially reflects that of Delta <sub>1</sub><sup>-1</sup> and Delta <sub>2</sub><sup>-1</sup>, respectively, because of the low covalency (f<sub>sigma </sub> approximately=2%). |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | How do the electronic properties of d<sup>9</sup> impurities depend on metal-ligand distances? Application to Ni<sup>+</sup>, Cu<sup>2+</sup> and Ag<sup>2+</sup> systems |
| Тип | paper |
| DOI | 10.1088/0953-8984/4/46/016 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 4 |
| Первая страница | 9089 |
| Последняя страница | 9112 |
| Аффилиация | J A Aramburu; Fac. de Ciencias, Univ. de Cantabria Univ., Santander, Spain |
| Аффилиация | M Moreno; Fac. de Ciencias, Univ. de Cantabria Univ., Santander, Spain |
| Аффилиация | M T Barriuso; Fac. de Ciencias, Univ. de Cantabria Univ., Santander, Spain |
| Выпуск | 46 |
