Knowledge Bank

Circularly polarized luminescence (CPL) and total luminescence (TL) spectra are reported for the intra-f-shell $\mathrm{<mrow\; data-mjx-texclass="ORD">7</mrow>}FJ\leftarrow 5DJ$ transitions of $Eu3+$ and of $Tb3+$ in crystalline $Na3Ln(C4H4O5)3\cdot 2NaClO4\cdot 6H2O$, where $Ln=Eu3+$ or $Tb3+$. The lanthanides in this system are each 9-coordinate with each tris(tridentate) $Ln(C4H4O5)3$ complex having exact trigonal dihedral ($D3$) symmetry. At room temperature the crystals are trigonal (space group $R322$) with three $Ln(C4H4O5)3$, species per unit cell. The $\mathrm{<mrow\; data-mjx-texclass="ORD">7</mrow>}FJ\leftarrow 5DJEu3+$ and $Tb3+$ transitions in this system exhibit very strong optical activity (as observed by CPL) reflecting unit cell dissymmetry as well as inherent chirality within each $Ln(CH4O5)3$ species. Temperature dependent CPL and TL measurements suggest a phase transition occurs in the crystal at about 110K.