# Color Centers and Jahn-Teller Effect in Ionic Crystals—My Scientific Encounters with Alex Müller

## Abstract

**:**

## 1. A Group Seminar at the University of Geneva

## 2. What I Learned at the Seminar

## 3. Interaction with Alex Müller during His Activity at IBM Rüschlikon

## 4. A Few Common Scientific Interests

## 5. Concluding Remarks

## Funding

## Acknowledgments

## Conflicts of Interest

## Appendix A. The 1992 Jahn-Teller Symposium in Ovronnaz, Switzerland

**Figure A1.**Participants of the 1992 Jahn-Teller symposium organized by the author in Ovronnaz, Switzerland. Alex Müller is in the first row, sixth from the left. His wife Inge is on his left. The author and his wife are next on his right. The complete list of participants is in the appendix.

## References

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**Figure 2.**With permission, from Reference [22]. Electron Paramagnetic Resonance (EPR) spectra of Eu${}^{2+}$ in SrFCl (

**top**) and BaFCl (

**bottom**). Measurements were made at 4.2 K with magnetic field parallel to the C${}_{4}$ axis.

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Bill, H. Color Centers and Jahn-Teller Effect in Ionic Crystals—My Scientific Encounters with Alex Müller. *Condens. Matter* **2020**, *5*, 59.
https://doi.org/10.3390/condmat5040059

**AMA Style**

Bill H. Color Centers and Jahn-Teller Effect in Ionic Crystals—My Scientific Encounters with Alex Müller. *Condensed Matter*. 2020; 5(4):59.
https://doi.org/10.3390/condmat5040059

**Chicago/Turabian Style**

Bill, Hans. 2020. "Color Centers and Jahn-Teller Effect in Ionic Crystals—My Scientific Encounters with Alex Müller" *Condensed Matter* 5, no. 4: 59.
https://doi.org/10.3390/condmat5040059