I'm wondering what are the typical examples (experiments) for magnetic dipole transitions and electric quadrupole transitions in crystals?


2 Answers 2


Observation of a pure electric quadrupole mechanism for a solid-state electronic transition

A pure electric quadrupole electronic transition was observed for single crystals of $\ce{Cs2UO3Cl4}$.

In the conclusion, the authors wrote:

Finally we wish to comment on the possible occurrence of other examples of this mechanism. The relative magnitude of the electric-quadrupole intensity compared to magnetic-dipole intensity will increase with increasing atomic radius and most examples will therefore be found in the lanthanide or actinide series.

  1. R. G. Denning, T. R. Snellgrove, D. R. Woodwark, Observation of a pure electric quadrupole mechanism for a solid-state electronic transition, Mol. Phys. 30, 1819–1828 (1975).

Other example in the literature is $\ce{Cs2NaSmCl6}$:

  1. R. W. Schwartz, A. K. Banerjee, Observation of a possible pure electric quadrupole transition in solid Cs2NaSmCl6, Chem. Phys. Lett. 79, 19–21 (1981).

  2. P. A. Tanner, G. G. Siu, Electric quadrupole allowed transitions of lanthanide ions in octahedral symmetry, Mol. Phys. 75, 233–242 (1992).


For magnetic dipole transitions, it seems well-known examples are Eu3+ doped phosphors, for example, Eu3+:Y2O3 and Eu3+ chelates. The $^5D_0 \rightarrow ^7F_1$ transition is magnetic dipole allowed, which is competitive to the $^5D_0 \rightarrow ^7F_2$ electric dipole transition, as shown in the following figure.

MD transition

This is a kind of examples that almost resembles atomic nature, although embeded in a crystal environment. Anyway, could be a reference.

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