Anandalakshmi H, Rajendiran T M, Venkatesan R, Rao P S
Department of Chemistry, Pondicherry University, R.V. Nagar, Kalapert, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2000 Dec;56(14):2617-25. doi: 10.1016/s1386-1425(00)00269-9.
Single crystal EPR studies of VO(II)-doped magnesium potassium Tutton's salt have been carried out at room temperature. The results indicate that the paramagnetic impurity has entered the lattice, both substitutionally and interstitially and the maximum hyperfine for the substitutional site along the a axis corresponds to the minimum hyperfine for interstitial site and vice versa. The spin Hamiltonian parameters obtained from single crystal data for these sites are: Site 1, gparallel = 1.954(1); gperpendicular = 1.998(1), Aparallel = 19.80(2) mT; Aperpendicular = 7.61(2) mT; Site 2, gparallel = 1.997(1); gperpendicular = 1.952(1), Aparallel = 7.66(2) mT; Aperpendicular = 19.85(2) mT. Superhyperfine from ligand protons have been observed at certain orientations for Site 2 impurity. Powder spectrum shows a set of eight parallel and perpendicular features indicating the presence of only one site and these values matched with Site 1 values. From these observations, it has been concluded that the two vanadyl impurities are approximately at right angles to each other. Cooling the sample to 77 K does not change the spectra appreciably. The admixture coefficients have been calculated from Site 1 data, which agree well with the reported values.
在室温下对掺VO(II)的镁钾铁矾盐进行了单晶电子顺磁共振研究。结果表明，顺磁性杂质已进入晶格，既有替代型的也有间隙型的，沿a轴替代位点的最大超精细与间隙位点的最小超精细相对应，反之亦然。从这些位点的单晶数据获得的自旋哈密顿参数如下：位点1，g平行 = 1.954(1)；g垂直 = 1.998(1)，A平行 = 19.80(2) mT；A垂直 = 7.61(2) mT；位点2，g平行 = 1.997(1)；g垂直 = 1.952(1)，A平行 = 7.66(2) mT；A垂直 = 19.85(2) mT。在特定取向下观察到位点2杂质的配体质子产生的超超精细现象。粉末谱显示出一组八个平行和垂直特征，表明只存在一个位点，且这些值与位点1的值相符。从这些观察结果可以得出结论，两个钒酰杂质彼此近似成直角。将样品冷却至77 K并没有明显改变光谱。根据位点1的数据计算出了混合系数，其与报道值吻合良好。
