Theodor Förster (15 May 1910 – 20 May 1974) was a German

physical chemist Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mecha ...

known for theoretical work on light-matter interaction in molecular systems such as

fluorescence Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with colore ...

and resonant energy transfer.

Education and career

Förster was born in

Frankfurt am Main Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...

and studied physics and mathematics at the University of Frankfurt from 1929 to 1933. He received his Ph.D. at the age of only 23 under

Erwin Madelung Erwin Madelung (18 May 1881 – 1 August 1972) was a German physicist. He was born in 1881 in Bonn. His father was the surgeon Otto Wilhelm Madelung. He earned a doctorate in 1905 from the University of Göttingen, specializing in crystal struct ...

in 1933. In the same year he joined the

Nazi Party The Nazi Party, officially the National Socialist German Workers' Party ( or NSDAP), was a far-right politics, far-right political party in Germany active between 1920 and 1945 that created and supported the ideology of Nazism. Its precursor ...

and the SA. He then joined

Karl-Friedrich Bonhoeffer Karl-Friedrich Bonhoeffer (13 January 1899 – 15 May 1957) was a German chemist. Biography Family, education and early career Born in Breslau, he was an older brother of martyred theologian Dietrich Bonhoeffer. His father was neurologist K ...

as a research assistant at the

Leipzig University Leipzig University (), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December 1409 by Frederick I, Electo ...

, where he worked closely with

Peter Debye Peter Joseph William Debye ( ; born Petrus Josephus Wilhelmus Debije, ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry. Biography Early life Born in Maastricht, Neth ...

Werner Heisenberg Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II. He pub ...

, and Hans Kautzky. Förster obtained his habilitation in 1940 and became a lecturer at the

. Following his research and teaching activities in Leipzig, he became a professor at the

Poznań University Poznań ( ) is a city on the Warta, River Warta in west Poland, within the Greater Poland region. The city is an important cultural and business center and one of Poland's most populous regions with many regional customs such as Saint John's ...

occupied Poland ' (Norwegian language, Norwegian: ') is a Norwegian political thriller TV series that premiered on TV 2 (Norway), TV2 on 5 October 2015. Based on an original idea by Jo Nesbø, the series is co-created with Karianne Lund and Erik Skjoldbjærg. ...

(1942). From 1947 to 1951 he worked at the

Max Planck Institute The Max Planck Society for the Advancement of Science (; abbreviated MPG) is a formally independent non-governmental and non-profit association of German research institutes. Founded in 1911 as the Kaiser Wilhelm Society, it was renamed to the M ...

for Physical Chemistry in

Göttingen Göttingen (, ; ; ) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. According to the 2022 German census, t ...

as a department head. In 1951, he became a professor at the

University of Stuttgart The University of Stuttgart () is a research university located in Stuttgart, Germany. It was founded in 1829 and is organized into 10 faculties. It is one of the oldest technical universities in Germany with programs in civil, mechanical, ind ...

. He died due to a heart attack in 1974.

Research

Among Förster's greatest achievements is his contribution to the understanding of FRET (

Förster resonance energy transfer Förster resonance energy transfer (FRET), fluorescence resonance energy transfer, resonance energy transfer (RET) or electronic energy transfer (EET) is a mechanism describing energy transfer between two light-sensitive molecules (chromophores). ...

). The term

Förster radius Förster or Foerster is a German surname meaning "forester". (It has often been Anglicised as Forster). Notable people of this name include: Förster * Arnold Förster (1810–1884), a German entomologist * August Förster (physician) (1822–186 ...

, which is related to the FRET phenomenon, is named after him. He also proposed the Förster cycle to predict the

acid dissociation constant In chemistry, an acid dissociation constant (also known as acidity constant, or acid-ionization constant; denoted ) is a quantitative property, quantitative measure of the acid strength, strength of an acid in Solution (chemistry), solution. I ...

of a

photoacid Photoacids are molecules that become more acidic upon absorption of light. Either the light causes a photodissociation to produce a strong acid, or the light causes photoassociation (such as a ring forming reaction) that leads to an increased acid ...

. He also discovered

excimer An excimer (originally short for excited dimer) is a short-lived polyatomic molecule formed from two species that do not form a stable molecule in the ground state. In this case, formation of molecules is possible only if such atom is in an elec ...

formation in solutions of

pyrene Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is . This yellow-green solid is the smallest peri-fused PAH (one where the rings are fused thro ...

Work

Book

* Förster, Theodor: ''Fluoreszenz organischer Verbindungen.'' Göttingen: Vandenhoeck & Ruprecht, 1950. – Unveränd. Nachdr. d. 1. Aufl., im Literaturverz. erg. um spätere Veröff. d. Autors. Göttingen: Vandenhoeck & Ruprecht, 1982 – *

Papers

* *

Literature

* A. Weller: Nachruf auf Theodor Förster. In: ''Berichte der Bunsengesellschaft für Physikalische Chemie'' 78 (1974) p. 969 ith Porträt * George Porter: Some reflections on the work of Theodor Förster. In: ''Die Naturwissenschaften'' 63 (1976) 5, p. 207–211.

References

{{DEFAULTSORT:Forster, Theodor 1910 births 1974 deaths German physical chemists Goethe University Frankfurt alumni Nazi Party members Academic staff of Leipzig University Max Planck Institutes researchers Academic staff of the University of Stuttgart Academic staff of Adam Mickiewicz University in Poznań German theoretical physicists Chemical physicists Max Planck Institute directors Scientists from Frankfurt