掺入Ni^(2+)和V^(3+)对α-Al_2O_3晶体光谱精细结构、晶体局域结构和零场分裂参量的影响

Effects of Doping α-Al_2O_3 Crystal with Ni^(2+) or V^(3+) Ion on Spectral Fine Structure Local Structure and Zero-Field Splitting Parameters

应用晶体场理论和不可约张量算符方法构造了3d2/3d8态离子在C3v对称晶场中包含自旋-轨道相互作用、自旋-自旋相互作用、自旋-其它轨道相互作用和其它轨道-其它轨道相互作用四种微观磁效应的45阶可完全对角化的能量哈密顿矩阵.利用该矩阵,计算了V3+∶α-Al2O3和Ni2+∶α-Al2O3晶体的光谱精细结构、晶体局域结构和零场分裂参量,研究了掺入两种互补态离子Ni2+和V3+对同种晶体的光谱精细结构、晶体局域结构和零场分裂参量的影响,理论计算值和实验值相符.研究发现:掺杂没有改变晶体的光谱精细结构和能级分裂条数,但改变了能级间距;掺杂也没有改变晶体的对称性,但使晶体局域结构发生了一定程度的畸变;Ni2+∶α-Al2O3晶体局域结构的伸长畸变量大于V3+∶α-Al2O3晶体,键角的变化量小于V3+∶α-Al2O3晶体.

Applying crystal field theory and irreducible representation method,the completely diagonalized Hamiltonian matrices of 3d2/3d8 ion configurations in the trigonal symmetry sites are established,which includes four kinds of microscopic magnetic interactions：spin-orbit interaction,spin-spin interaction,spin-other-orbit interaction and other orbit-other orbit interaction.The spectral fine structure,local structure and zero-field splitting parameters of V3＋：α-Al2O3 and Ni2＋：α-Al2O3 crystals are investigated as well as the influence of the doping.The results show that doping complementary ions can not change the fine structure of spectra and the symmetry of crystal structure but the spectral splits and local structure of crystal.The local structure stretch distortion in Ni2＋：α-Al2O3 is larger than that of V3＋：α-Al2O3 crystal while the angle change is less.