The Special Case of the Spectral Emission of a Tb 3+ Mono Metal Complex.

The fine structure in the spectral lines of the visible fluorescence of Tb 3+ complexes are replaced by a single peak in the case of a singular molecular complex Tb(H 3 PTC) 3 , where H 4 PTC represents perylene-3,4,9,10-tetracarboxylic acid, and its emission wavelength depends on the film thickness. This single peak challenges the old creed that the f-orbital electrons of Tb 3+ are always protected from the influence of the surrounding atoms. We perform density functional theory calculations to show that the wavefunction of the ground state is localized and in addition, spin-polarized, and this facilitates fluorescent transitions under UV to the first excited state instead of the fundamental state. We discuss the possibility of making a spintronic device with the molecule, Tb(H 3 PTC) 3 .