Gottfried Möllenstedt

from Wikipedia, the free encyclopedia

Gottfried Möllenstedt (born September 14, 1912 in Versmold ; † September 11, 1997 in Tübingen ) was a German physicist and professor at the Eberhard Karls University of Tübingen . From 1966 to 1968 he was its rector .

Birthplace of Gottfried Möllenstedt in Versmold

Life

Gottfried Möllenstedt, born in Versmold in 1912, had two sisters and five brothers and was the fourth of eight children of the teacher, cantor and vice-principal Johann Heinrich Möllenstedt and his wife Katharine Ch. Alwine, born in the cantor house in Versmold. Schulte zur Surlage. Möllenstedt first attended elementary school and later a private school in Versmold, in order to then pass the Abitur in the municipal Helmholtz secondary school in Bielefeld. First he wanted to become an aircraft engineer, but then, impressed by his academic teachers Walther Kossel and Eberhard Buchwald , turned to physics in 1934. Under Walther Kossel he passed the main diploma examination (Dipl.-Ing.) At the TH Danzig in 1939 and received his doctorate with the dissertation Measurements of the interference phenomena in the convergent electron bundle for Dr.-Ing. on December 17, 1940. First, however, Gottfried Möllenstedt had become more conspicuous in his early semesters due to his sporting activities in the short distances and with 10.6 s over 100 m at the time as "Danzig's fastest sprinter" even in the preliminary round for the 1936 Olympics On October 11, 1940, he married the teacher Dorothea Tanner in Danzig. From 1939 to 1945 he was Kossel's research assistant in Danzig and on January 30, 1945, with the inaugural thesis New Applications of Geometric Electron Optics for Interference Problems, he became a private lecturer Dr.-Ing.habil. appointed. At the beginning of February 1945, the Phys. Inst. Under Walther Kossel, together with Möllenstedt, took the beleaguered city of Danzig on the flight ship Germany to build an alternative laboratory , the research center for metals at the salt bridge , via Kiel in Schmalkalden in Thuringia , from where about 70 scientists on June 23, 1945 through the American military administration to be interned in Heidenheim . His internment ends in October 1945.

In 1947 Möllenstedt got his first job as a research assistant and department head of the laboratories for electronics of the southern German laboratories (SDL) from AEG / Zeiss in Mosbach and continued to maintain contact with W. Kossel in Tübingen. In the spring of 1950 he was appointed lecturer for experimental physics in Math.-Naturwiss. Faculty of the Eberhard-Karls-Universität Tübingen, 1953 as associate professor for applied physics and 1960 as full professor and director of the institute for applied physics. In 1963 Gottfried Möllenstedt became dean of Math.-Naturwiss. Faculty and in the same year also organized the anniversary celebrations of its 100th anniversary (the oldest natural science faculty in Germany). From 1966 to 1967 and after re-election from 1967 to 1968 he was rector of the university. Between 1963 and 1971 he also took over the post of acting director of the vacant astronomy chair at the University of Tübingen. From 1964 he was chairman of the building commission of the University of Tübingen for six years and in 1972 he was able to move into the newly established Institute for Applied Physics in the morning place . In 1980 Gottfried Möllenstedt retired and died on September 11, 1997 after a long and serious illness in Tübingen. His wife Dorothea and his two sons Ulrich and Manfred were among the mourners at the Bergfriedhof in Tübingen.

Möllenstedt and his institute had an international leadership role in his research area and wrote around 200 scientific papers as an author or co-author. In addition, around 250 diploma and public examination papers and around 100 doctoral theses and around a dozen habilitation theses are supervised.

plant

Already in Gdansk he deals with electron diffraction in his diploma thesis, and his diffraction patterns have already been called Kossel-Möllenstedt interferences. A high-resolution velocity and energy analyzer for electrons (Möllenstedt's velocity analyzer) developed by him in 1948/49 enabled the observation of plasmons , which cause characteristic energy losses of electrons when passing through solids. In 1950, in Mosbach, Gottfried Möllenstedt made a momentous observation in which an electron beam is unintentionally split by a thin tungsten wire and creates a double image. From this effect he developed the Möllenstedt biprism, with which his doctoral student Heinrich Düker (1923–1985) received a first interference image in 1954 , because a spider thread (later glass thread) coated with gold splits the electron beam and, when it is positively charged, divides the partial bundles again Overlap and thus brings to interference. 1956 thanks Louis de Broglie for the experimental confirmation of the validity of his formula for the electron wavelength λ = h / (m · v) by means of a biprism improved by cylindrical lenses. This prism made Gottfried Möllenstedt a pioneer of electron interferometry , and many wave-optical phenomena of electrons were investigated with it at his institute in Tübingen. For his experiments he developed electron and ion beam lithography together with R. Speidel around 1960 ; a little later, together with W. Bayh, he achieved biprism interference with widely separated coherent electron sub-bundles and in 1962 detection and measurement of the continuous phase shift of electron waves in the Space free of force fields due to the magnetic vector potential of an air coil ( Aharonov-Bohm effect ). As a doctoral supervisor, he supervised an experiment carried out by Claus Jönsson in 1959 on the interference of electrons at the self-supporting double slit. This was voted the most beautiful physics experiment of all time in a 2002 survey by "Physics World", published by the English Physical Society . Furthermore, Fresnel zone plates for soft X-ray radiation and, together with Hannes Lichte, fundamental work on electron holography were carried out at his institute .

The electron microprobes used, for example, in material analysis, which are based on the principle of diffraction with convergent beams (micro-diffraction, convergent beam diffraction, CBD), generate depending on whether the irradiation aperture of the incident electrons is smaller or larger than the diffraction angle separate diffraction disks (Kossel-Möllenstedt diagram, if the aperture is smaller than the diffraction angle) or diffraction disks to be overlapped (Kossel diagram, if the aperture is larger than the diffraction angle).

Honors and memberships

In 1938 Gottfried Möllenstedt became a member of the German Physical Society (DPG), 1958 Chairman of the German Society for Electron Microscopy (DGE), 1969 representative of the German Research Foundation at the University of Tübingen, 1973 representative of the University in the University Association, 1979 member of the German Academy of Natural Scientists Leopoldina and 1986 honorary member of the Japanese Society for Electron Microscopy.

In 1961, G. Möllenstedt and R. Speidel received the Outstanding Award for the development of electron beam lithography at the International Solid State Circuit Conference in Philadelphia . In 1987 the European Science Prize of the Hamburg Körber Foundation was awarded to two research groups (one in Finland and one in Germany). a. also to Möllenstedt. In 1995 Gottfried Möllenstedt received the Cothenius Medal of the German Academy of Sciences Leopoldina for his pioneering work in the field of electron optics and electron microscopy.

Fonts

  • G. Möllenstedt: Measurements on the interference phenomena in the convergent electron bundle , Annalen der Physik, Volume 40, 1941, pp. 17-43
  • G. Möllenstedt: Precision comparison of lattice constants by means of pinhole camera interference , Optik, Volume 1, 1946, pp. 76 - 84
  • G. Möllenstedt: Cinematography and fully automatic series recordings of rapidly changing electron interferences , Optics, Volume 3, 1948, pp. 68 - 74
  • G. Möllenstedt, F. Heise: The electrostatic lens as a high-resolution speed analyzer , Physikalische Blätter, Volume 5, 1949, pp. 80-93
  • G. Möllenstedt: Optics of the electron intermediate accelerator for imaging, diffraction and spectrometry , Phys. Verh. 3, 9, 1952
  • G. Möllenstedt: Discrete energy losses of 35 keV electrons when interacting with atoms and molecules , Zeitschrift für Naturforschung, Volume 7A, 1952, pp. 465-470
  • G. Möllenstedt, M. Keller; Electron interferometric measurement of the internal potential , Zeitschrift für Physik, Volume 148, 1957, pp. 34-37
  • G. Möllenstedt, R. Speidel, W. Koch: Standing waves according to O. Wiener, made electron-optically visible , Zeitschrift für Physik, Volume 149, 1957, pp. 377-382
  • R. Buhl, G. Möllenstedt: An electron interference microscope , Physikalische Blätter, August 1957
  • G. Möllenstedt, C. Jönsson: Electron multiple interferences on regularly produced fine slits , Zeitschrift für Physik, Volume 155, 1959, pp. 472-474
  • G. Möllenstedt, R. Speidel: Electron-optical micro-writer under electron-microscopic work control: (information storage in the smallest of spaces) , Physikalische Blätter, Volume 16, April 1960, pp. 192-198
  • G. Möllenstedt, W. Bayh Electron biprism interference with widely separated coherent sub-bundles , Die Naturwissenschaften, Volume 48, 1961, p. 400
  • G. Möllenstedt, W. Bayh Measurement of the continuous phase shift of electron waves in space free of force fields by the magnetic vector potential of an air coil , Die Naturwissenschaften, Volume 49, 1962, p. 81, 1962,
  • G. Möllenstedt, KH v. Grote, C. Jönsson: Production of Fresnel Zone Plates for Extreme Ultraviolet and Soft X Radiation, X-Ray Optics and X-Ray Microanalysis , in H. Pattee u. a. (Ed.), X-Ray Optics and X-Ray Microanalysis, Academic Press, New York 1963, pp. 73-79
  • G. Möllenstedt, H. Wahl Electron holography and reconstruction with laser light , Die Naturwissenschaften, Volume 55, 1968, pp. 340 - 341
  • G. Möllenstedt, H. Lichte, H. Wahl A Michelson Interferometer Using Electron Waves , Zeitschrift für Physik, Volume 249, 1972, pp. 456 - 461
  • G. Möllenstedt, H. Lichte Young - Fresnel interference experiment with two adjacent mirrors for electron waves , Optics, Volume 51, 1978, pp. 423-428

literature

  • Dietrich Schulze: Gottfried Möllenstedt's electron-optical biprism, key to wave optics from electron interferometry to holography. Electron microscopy, No. 30, 2010, p. 15, pdf (web archive)
  • Jan van der Lip: Sport, Physics and Optimism - Gottfried Möllenstedt. Printsystem Medienverlag, Heimsheim 2012, 238 pp. ISBN 978-3-938295-54-0
  • H. Seiler: Gottfried Möllenstedt 60 years, Physikalische Blätter, October 1972, p. 470, online

Individual evidence

  1. ↑ Möllenstedt, Düker Fresnel interference test with a biprism for electron waves , Die Naturwissenschaften, Volume 42, 1954, p. 41
  2. ^ Möllenstedt, Düker, observations and measurements of biprism interference with electron waves , magazine f. Physics, Volume 145, 1956, p. 377
  3. ↑ Most beautiful physical experiment ever carried out in Tübingen
  4. ↑ Helmut Günzle et al. (Ed.), Analytiker-Taschenbuch, Volume 14 , Springer, 1996, p. 205 (chapter by J. Heydenreich, Transmission Electron Microscopy)

Web links

personal data
SURNAME Möllenstedt, Gottfried
BRIEF DESCRIPTION German physicist and university professor
DATE OF BIRTH September 14, 1912
PLACE OF BIRTH Versmold
DATE OF DEATH September 11, 1997
Place of death Tübingen