| Autor: |
Teki, Yoshio, Takui, Takeji, Itoh, Koichi |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 5/15/1988, Vol. 88 Issue 10, p6134, 12p |
| Abstrakt: |
A spin Hamiltonian consisting of the Zeeman and fine-structure terms is solved for an arbitrary spin S using third-order perturbation theory (|D|≪hν). From this solution, general analytical expressions are derived for the occurrence of off-axis extra lines in ESR fine structure. These appear under certain conditions in powder-pattern ESR spectra besides the canonical lines associated with principal axes of g and fine-structure tensors. The occurrence conditions, which essentially come from the second-order term in the fine-structure energy, are given for the allowed (ΔMs=±1) and forbidden (ΔMs=±2) transitions without restrictions previously assumed in the literature, viz., an axially symmetric fine-structure tensor, an isotropic g tensor, or a limited S. It is shown that extra lines tend to appear with an increasing S, an increasing fine-structure energy, and a decreasing microwave frequency. Spectral simulation also reveals that for high-spin systems (S>1) extra lines commonly appear at the X band with comparable or even stronger intensities compared with normal canonical lines, so that inclusion of extra lines is necessary for analysis of powder-pattern spectra from such systems. Diagrams illustrating the appearance area in fine-structure parameters are presented for S=3/2 to 4 and are used to analyze the data reported so far; these diagrams may greatly assist an understanding of such high-spin spectra. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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