Hermann Gerhard Hertz

Hermann Gerhard Hertz

Hermann Gerhard Hertz (born June 13, 1922 in Hamburg ; † January 2, 1999 in Karlsruhe ) was a German physical chemist.

His main field of work was physical chemistry , especially electrochemistry . In Germany he was one of the pioneers in the field of nuclear magnetic resonance (NMR). From 1980 he was a member of the editors' committee of the Zeitschrift für Physikalische Chemie . He is the great-nephew of the well-known physicist and discoverer of electromagnetic waves, Heinrich Hertz , and the nephew of the physicist and Nobel Prize winner Gustav Hertz .

Life

Hermann Gerhard Hertz was born in Hamburg as the son of a long-established family, which consisted primarily of business people and lawyers, but also produced two famous physicists. After graduating from high school in 1940, he immediately became a soldier, and after the end of the war and imprisonment , he studied physics at the university in his hometown from 1945 to 1950 , where he also wrote his diploma thesis under Paul Harteck in 1950 and his dissertation on the development of a fog or in 1952 Wilsonkammer completed.

From 1960 he was a research assistant at the University of Muenster , where he was in the same year in physical chemistry habilitated . In 1964, HG Hertz became an associate professor at the University of Münster and in 1965 he was given a full professorship at the TH Karlsruhe , so coincidentally at the place where his great-uncle Heinrich Hertz had detected the electromagnetic waves in 1886 . Although HG Hertz was appointed to the University of Munich in 1970 , he remained loyal to the University of Karlsruhe until his retirement in October 1990.

It is worth noting that HG Hertz always had extremely good relationships with foreign scholars and had long research stays in Canberra, Australia and Trondheim, Norway. In particular, he kept in contact with working groups in the Soviet Union through frequent lecture tours. Through his uncle Gustav Hertz, who lived in Leipzig, he had particularly good relationships with the University of Leipzig and with the large NMR research group around Artur Lösche and Harry Pfeifer working there .

Act

During his time as an assistant in Hamburg, HG Hertz initially dealt with the separation of gases using the gas centrifuge, but soon turned to the emerging NMR investigation method and thus became one of the pioneers in this field in Germany. A stay in the laboratory of Herbert S. Gutowsky in Urbana, USA, one of the great NMR pioneers, helped him in 1957 . In his habilitation thesis, HG Hertz investigated the line widths of atomic nuclei in monatomic ions such as Br ^- or I ^- (these atomic nuclei have an electrical quadrupole moment ) in aqueous electrolyte solutions and provided the first theory of relaxation (NMR) by electrostatic quadrupole interaction, today "Hertz-Valiev- Called theory ". With this, HG Hertz opened up the broad field of the investigation of electrolyte solutions by means of ion core relaxation. To study the translational microdynamics in electrolyte solutions and other fluid systems by means of diffusion measurements, Hertz used field gradient NMR relatively early and thus investigated " structure breakage " and " structure formation " of salts in aqueous electrolytes. HG Hertz and his research group also made important contributions to understanding the structure and dynamics of the solvation shell of non-polar particles or groups of molecules in water. The "hydrophobic hydration" and "hydrophobic association" (see: hydrophobic effect ), were investigated in the Hertz group mainly by means of proton relaxation (NMR) and play an extremely important role in biological processes, such. B. in biomembrane formation and protein folding .

During the 1970s and 1980s, the Hertz Laboratory in Karlsruhe developed into one of the world's leading laboratories for studying self-diffusion in liquids. Since 1976 HG Hertz has also theoretically investigated problems of diffusion and electrical conductivity and formulated his results using the "velocity correlation function ". In this context, he encountered difficulties with quantities and concepts in conventional electrochemistry that are not accessible to direct measurement. In a book published in 1980. Hertz completely reformulated the basic principles of electrochemistry. It is very interesting that the term " electrical charge " does not appear in this reformulated electrochemistry, it is not needed. These reformulations and, above all, Hertz's work on the extra conductivity of the H + ion were received controversially among experts.

Very early on, HG Hertz also provided a comparative theoretical presentation of the spin echo diffusion experiment in field gradient NMR with inelastic neutron scattering , thus anticipating later developments.

In the last years of his life, Hermann Gerhard Hertz also dealt intensively with the work of his great-uncle Heinrich Hertz from a scientific-historical point of view. He published his laboratory notes from 1887 and a previously unpublished lecture on the energy balance of the earth.

Hermann Gerhard Hertz has written a total of 197 scientific papers. His students include the German physical chemists Manfred Zeidler , Heinrich Versmold, Helmut Bertagnolli, Alfons Geiger , Manfred Holz and Hermann Weingärtner.

literature

• Physical Chemistry Journal . Volume 214, 2000, p. 894 (obituary)
• H. Versmold, MD Zeidler: Hermann Gerhard Hertz on his 65th birthday. In: Ber. Bunsenges. Phys. Chem. 91, 1987, pp. 593-595.

Web links

• Ulrich Schindewolf: 100 years of the Institute for Physical Chemistry at the University of Karlsruhe. In: Bunsen magazine. 2nd year, 6/2000, p. 145. (PDF; 109 kB)
• Literature by and about Hermann Gerhard Hertz in the catalog of the German National Library

Individual evidence

1. ↑ HG Hertz: Approach distances of ions in aqueous solutions from the line width of nuclear magnetic resonance. In: Z.Elektrochem. Ber. Bunsenges. Phys. Chem. 65, 1961, pp. 20-36.
2. ↑ M. Holz: Electrolytes. In: DM Grant, RK Harris (Ed.): Encyclopedia of Nuclear Magnetic Resonance. J. Wiley and Sons, Vol. 3, 1996, pp. 1857-1864.
3. ↑ L. Endom, HG Hertz, B. Thül, M. Zeidler: A Microdynamic Model of Electrolyte Solutions as Derived from Nuclear Magnetic Relaxation and Self-Diffusion Data. In: Ber. Bunsenges. Phys. Chem. 71, 1967, p. 1008.
4. ↑ HG Hertz: The structure of the solvation envelope of dissolved particles. In: Angew.Chem. 82, 1970, pp. 91-106.
5. ^ HG Hertz: Electrochemistry, A Reformulation of the Basic Principles. In: Lecture Notes in Chemistry 17. Springer-Verlag, Berlin / Heidelberg / New York 1980, ISBN 3-540-10008-3 .
6. ^ HG Hertz, MG Doncel: Heinrich Hertz's Laboratory Notes of 1887. In: Archive for History of Exact Sciences. 49, 1995, pp. 197-270.
7. ↑ JF Mulligan, HG Hertz: An Unpublished Lecture by Heinrich Hertz: On the Energy Balance of the Earth. In: Am. J. Phys. 65, 1997, pp. 36-45.