Monoisotopic $$^{53}\hbox {Cr}^{3+}$$ 53 Cr 3 + impurity ions in scandium orthosilicate single crystal ( $$\hbox {Sc}_2\hbox {SiO}_5$$ Sc 2 SiO 5 ) are studied by the method of electron paramagnetic resonance in the X-band frequencies. The directions of the main principal magnetic axes and the parameters of the effective spin Hamiltonian that describe the magnetic characteristics of the impurity centers of chromium, which replaces scandium in two structurally nonequivalent positions, are determined. It is shown that the orientation dependencies of the EPR spectra are well described by the second-order spin Hamiltonian corresponding to the orthorhombic symmetry of the local crystal field acting on the impurity ion. It was assumed that the g -tensor and the A -tensor determining the Zeeman energy of electronic levels in a magnetic field and the hyperfine interaction of electron and nuclear spins are isotropic, and the entire anisotropy of the EPR spectra is due to the anisotropy of the D -tensor, which describes the fine structure of electronic levels in a crystalline electric field. A strong dependence of the probability of “forbidden” transitions between hyperfine sublevels of electronic levels on the orientation of an external magnetic field is established. Moreover, for some orientations, the probability of “forbidden” transitions exceeds the probability of “allowed” transitions.

中文翻译：

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正硅酸钪单晶中 $$^{53}\hbox {Cr}^{3+}$$ 单同位素杂质离子的 EPR 光谱 $$\hbox {Sc}_{2}\hbox {SiO}_{5 }$$

单同位素 $$^{53}\hbox {Cr}^{3+}$$ 53 Cr 3 + 原硅酸钪单晶中的杂质离子 ( $$\hbox {Sc}_2\hbox {SiO}_5$$ Sc 2 SiO 5 ) 在 X 波段频率中通过电子顺磁共振的方法进行研究。确定了主要主磁轴的方向和有效自旋哈密顿量的参数，这些参数描述了铬杂质中心的磁特性，铬在两个结构上不等价的位置取代了钪。结果表明，EPR 光谱的取向依赖性可以通过与作用于杂质离子的局部晶体场的正交对称性相对应的二阶自旋哈密顿量来很好地描述。假设确定磁场中电子能级的塞曼能量的 g 张量和 A 张量以及电子和核自旋的超精细相互作用是各向同性的，并且 EPR 光谱的整个各向异性是由于D -张量，它描述了晶体电场中电子能级的精细结构。建立了电子能级的超精细子能级之间“禁止”跃迁的概率对外部磁场方向的强烈依赖性。此外，对于某些方向，“禁止”转换的概率超过“允许”转换的概率。它描述了晶体电场中电子能级的精细结构。建立了电子能级的超精细子能级之间“禁止”跃迁的概率对外部磁场方向的强烈依赖性。此外，对于某些方向，“禁止”转换的概率超过“允许”转换的概率。它描述了晶体电场中电子能级的精细结构。建立了电子能级的超精细子能级之间“禁止”跃迁的概率对外部磁场方向的强烈依赖性。此外，对于某些方向，“禁止”转换的概率超过“允许”转换的概率。