Philipp Gütlich (1934-2022)

Philipp Gütlich (1934-2022)

Our IBAME honorary member and former IBAME chair Philipp Gütlich passed away on 9 September 2022 at the age of 88. The international Mössbauer community loses not only an excellent scientist and committed teacher but also a friend and colleague who, with immense dedication, advanced the applications of the Mössbauer effect in a diversity of research fields.

Philipp Gütlich was born in 1934 in Rüsselsheim/Germany. He studied Chemistry at the Technische Hochschule Darmstadt and finished the PhD thesis in 1963. During a postdoctoral research stay in Brookhaven National Laboratory (USA) he became acquainted with possible applications of the Mössbauer effect in solid state research. This formed the basis of the Habilitation thesis Applications of the Mössbauer Effect in Chemistry presented at the University of Darmstadt in 1970. By two articles on the basics and applications of Mössbauer spectroscopy in the didactically oriented journal Chemie in unserer Zeit the method became well-known also in the community of chemists.

In 1972, Philipp Gütlich was appointed to the professorship of Theoretical Inorganic Chemistry at the Technische Hochschule Darmstadt and in 1975 he accepted a full professorship at the Institute of Inorganic Chemistry, University of Mainz.

In Mainz a Mössbauer laboratory was established comprising all specific methods. Mössbauer spectroscopy was applied to different problems of solid-state research also using isotopes other than ⁵⁷Fe such as ¹⁹⁷Au, ¹¹⁹Sn, ¹⁹³Ir, ¹⁵¹Eu and on-line measurements of ^83mKr implanted into Al. ⁶¹Ni Mössbauer spectroscopy was also utilised continually. Mainz became one of few places where time-differential Mössbauer emission spectroscopy (TDMES) was developed and used to study after effects of the nuclear decay ⁵⁷Co → ⁵⁷Fe in inorganic solids.

Philipp Gütlich’s main interest was thermal, light- and pressure-induced spin transition phenomena of iron(II) coordination compounds. All aspects were investigated experimentally with several measuring techniques including optical (IR, FAR-IR, Raman) and Brillouin spectroscopy. A FONER magnetometer was optimized, a pressure cell for Mössbauer measurements and a microcalorimeter for single crystals in the mg-range specially designed for materials of low thermal conductivity were developed. The interaction mechanism of the cooperative transitions was identified as elastic interaction between molecules of different size and shape in high and low-spin electronic states. The term spin crossover became connected to the name Gütlich.

Most spectacular has turned out the miniaturization of a Mössbauer spectrometer (MIMOS) scaled down by a factor of almost 100 as compared to a laboratory spectrometer. When Mars missions were planed in the nineties, Prof. Egbert Kankeleit at the Technical University Darmstadt started the development. After his retirement, Philipp Gütlich could convince Dr. Göstar Klingelhöfer from the Kankeleit group to join his group in Mainz and continue the project. After many successful terrestrial applications, NASA and the European Space Agency ESA decided that MIMOS would participate in the NASA missions Spirit and Opportunity. About a dozen iron-containing minerals were identified, among them typical ones which only could have developed in wet surroundings, an indirect evidence that water must had been present on Mars.

When Dr. Werner Meisel, the representative of the Mössbauer community of the German Democratic Republic (GDR) illegally left the GDR after the International Conference on Mössbauer Spectroscopy in Portorož, Yugoslavia in 1979, Philipp Gütlich successfully applied for him for an adequate research position in his group and could equip the laboratory with a combined ESCA-Auger-Mössbauer Spectrometer. The research fields were extended to sophisticated surface physics on corrosion of steel surfaces and structure of glasses.

On the occasion of the 20^th birthday of the Mössbauer effect Philipp Gütlich initiated the Seeheim Workshop at the Lufthansa Training Center in Seeheim. The workshop held every 5 years was well accepted. Participants from all over the world still speak about the Gütlich Conference.

Philipp Gütlich published two books on Mössbauer Spectroscopy: Mössbauer Spectroscopy and Transition-Metal Chemistry together with Dr. Rainer Link and Prof. Alfred X. Trautwein in the Springer Series Inorganic Chemistry Concepts in 1978 and Mössbauer Spectroscopy and Transition Metal Chemistry – Fundamentals and Applications that appeared in 2011 in co-edition with Dr. Eckhard Bill and Prof. Alfred X. Trautwein.

Together with Prof. N. Sutin, Philipp Gütlich launched the journal Comments on Inorganic Chemistry in 1981 and acted as its editor. With Prof. Harold A. Goodwin from Sidney he edited the first comprehensive book comprising three volumes on Spin Crossover in Transition Metal Compounds, which appeared in 2004 in the Springer Series Topics in Current Chemistry.

Together with Prof. Olivier Kahn of the Université Paris Sud, Philipp Gütlich was honoured with the Max Planck Research Award for international cooperation for their top-level research in the field of spin crossover phenomena in 1993. The Honorary Doctor and Professor of the Eötvös Loránd University, Budapest and the Honorary Doctor of Toho University, Tokyo were awarded him as emeritus in 2003 and 2007, respectively.

Philipp Gütlich’s research is reflected in almost 500 publications of which 150 appeared after his retirement still cooperating with colleagues around the world. His research group (altogether ca. 20–25 scientific persons on average during 25 years in Mainz) always comprised chemists and physicists.

Distinguished researchers were invited for one-weak crash courses of their field relevant for the topics discussed in the group or longer stays for close interaction.

There was always time for social events, birthday celebrations at lunch prepared in the kitchen area of the common room, grill parties, field days and, at the end of the year, the Christmas party together with alumni coming from afar. The ski-seminars, mainly for skiing less for tutorials, belonged to the highlights. In the Gütlich group people were either able to ski or learned skiing. Philipp himself was an excellent skier. He went in for sports with some ambition: swimming, tennis and also field hockey with a German championship.

The Christmas party survived Philipp’s retirement and will also survive his final leave as a memorial event.

Dr. Hartmut Spiering (retired, joined the Gütlich group in 1978)