Application of High Frequency EPR to Integer Spin Systems: Unusual Behavior of the Double-Quantum Line

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• 作者：van Dam ; Pieter J. ; Klaassen ; Adri A. K. ; Reijerse ; Eduard J. ; Hagen ; Wilfred R.
• 刊名：Journal of Magnetic Resonance
• 出版年：1998
• 出版时间：January, 1998
• 年：1998
• 卷：130
• 期：1
• 页码：140-144
• 全文大小：143 K

文摘

A high-frequency EPR study is presented of the integer spin system Ni(II) in the host of Zn-tris(ethylenediamine) dinitrate. This complex shows a broad structureless line at X band. At D band (130 GHz) however, a standard triplet powder spectrum is observed. Superimposed on this spectrum is a “double-quantum” line at the expected position. The microwave power dependency of this line is found to be in contradiction with existing theory on multiple-quantum transitions. The line in our spectra shows a single quantum line behavior in intensity and linewidth as a function of the microwave frequency from 35 to 130 GHz. A literature survey leads to the conclusion that most double-quantum features in high-spin systems do not follow theP^3/2power dependency predicted by second-order perturbation theory. In our case the double-quantum line is assigned to an enhancement effect due to the simultaneous excitation of two single-quantum transitions.