Theodor Förster (May 15, 1910 – May 20, 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 me ...

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

fluorescence Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

and resonant energy transfer.

Education and career

Förster studied at the University of Frankfurt and 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 structu ...

in 1933. In the same year he joined the

Nazi Party The Nazi Party, officially the National Socialist German Workers' Party (german: Nationalsozialistische Deutsche Arbeiterpartei or NSDAP), was a far-right politics, far-right political party in Germany active between 1920 and 1945 that crea ...

and the SA. He then joined

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

as a research assistant at the

Leipzig University Leipzig University (german: Universität Leipzig), 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 ...

, where he worked closely with

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

Werner Heisenberg Werner Karl Heisenberg () (5 December 1901 – 1 February 1976) was a German theoretical physicist and one of the main pioneers of the theory of quantum mechanics. He published his work in 1925 in a breakthrough paper. In the subsequent series ...

, 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 River Warta in west-central Poland, within the Greater Poland region. The city is an important cultural and business centre, and one of Poland's most populous regions with many regional customs such as Saint John ...

occupied Poland ' (Norwegian: ') is a Norwegian political thriller TV series that premiered on TV2 on 5 October 2015. Based on an original idea by Jo Nesbø, the series is co-created with Karianne Lund and Erik Skjoldbjærg. Season 2 premiered on 10 October 2 ...

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

Max Planck Institute Max or MAX may refer to: Animals * Max (dog) (1983–2013), at one time purported to be the world's oldest living dog * Max (English Springer Spaniel), the first pet dog to win the PDSA Order of Merit (animal equivalent of OBE) * Max (gorilla) ...

for Physical Chemistry in

Göttingen Göttingen (, , ; nds, Chöttingen) 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. At the end of 2019, t ...

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

University of Stuttgart The University of Stuttgart (german: Universität Stuttgart) is a leading 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 wit ...

. He passed away 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, 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 measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction :HA ...

of a

photoacid Photoacids are molecules which 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 ac ...

. He also discovered

excimer An excimer (originally short for excited dimer) is a short-lived dimeric or heterodimeric molecule formed from two species, at least one of which has a valence shell completely filled with electrons (for example, noble gases). In this case, form ...

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 solid is the smallest peri-fused PAH (one where the rings are fused through mor ...

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 Theoretical physicists Chemical physicists Max Planck Institute directors