Knowledge Bank

“The absorption spectrum of $Cu2+$ has been studied in $CuSiF6\bullet 6H2O$, in a copper doped ZnO single crystal and in a Cu doped single crystal of YGG. From the absorption spectrum of $CuSiF6\bullet 6H2O$, the crystal field parameter for $Cu2+$ in octahedral coordination is deduced and used to predict the energy levels of $Cu2+$ in tetrahedral coordination according to the relation $Dq(tet)=-49Dq(oct)$. The accuracy of the prediction is excellent. A series of sharp intense lines is found at $5900cm-1$ for Cu in ZnO. The results are used to interpret the absorption of Cu in YGG where there is considerable evidence that $Cu2+$ is present in a tetrahedral site.”