Walther Kossel
Encyclopedia
Walther Ludwig Julius Kossel (4 January 1888 in Berlin
, Germany – 22 May 1956 in Tübingen
, Germany) was a German physicist
known for his theory of the chemical bond
(ionic bond
/octet rule
), Sommerfeld–Kossel displacement law of atomic spectra, the Kossel-Stranski model for crystal growth, and the Kossel effect. Walther was the son of Albrecht Kossel
who won the Nobel Prize in Physiology or Medicine
in 1910.
during 1907 and 1908. In 1910, he became assistant to Philipp Lenard
, who was also his thesis advisor. Kossel was awarded his Ph.D. in 1910, and he stayed on as assistant to Leonard until 1913.
In 1913, the year in which Niels Bohr
introduced the Bohr model
of the atom, Kossel went to the University of Munich as assistant to Arnold Sommerfeld
, under whom he did his Habilitation
. Under Sommerfeld, Munich was a theoretical center for the developing atomic theory
, especially from the interpretation of atomic spectra. In 1916, Kossel put forth his theory of the ionic chemical bond
(octet rule
), also independently advanced in the same year by Gilbert N. Lewis
. In papers published in 1914, 1916, and 1920, Kossel was the first to explain the theory of absorption limits in x-ray spectra. The edge appears at a critical frequency where absorption of the radiation largely begins with the resultant ejection of photoelectrons
. In 1919, Kossel and Sommerfeld explained the similarity of the atomic spectra of neutral atoms, of atomic number
Z, and singly ionized atoms, of atomic number Z + 1, which became known as the Sommerfeld–Kossel displacement law. In 1920, Kossel explained another phenomenon of x-ray spectra. Under high resolution spectroscopy, the absorption edge has structure. He attributed this to absorption of radiation by electrons which are not ejected from matter as photoelectrons, but are “kicked up” to higher, unoccupied, bound electron energy levels. In early years, this was known as “Kossel structure
.”
In 1921, Kossel took an appointment as ordinarius professor of theoretical physics at the University of Kiel
. In 1928, he put forth his kinetic theory of crystal growth, which became known as the Kossel-Stranski model – Iwan N. Stranski independently proposed the same model.
In 1932, Kossel took the appointment as ordinarius professor of theoretical physics at the Technische Hochschule
at Gdańsk
. During his tenure there in 1934, he discovered x-ray lattice interference of spherical waves in crystals during the bombardment of single-crystal copper with a high-energy electron beam.
In 1944, he was awarded the Max-Planck medal by the Deutsche Physikalische Gesellschaft
.
In 1945, Kossel became professor of theoretical physics and director of the Physics Institute at the University of Tübingen, where he was granted emeritus status in 1953.
Kossel died in Tübingen and is buried, as is his father, Albercht, in the Wald Friedhof, Heidelberg.
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
, Germany – 22 May 1956 in Tübingen
Tübingen
Tübingen is a traditional university town in central Baden-Württemberg, Germany. It is situated south of the state capital, Stuttgart, on a ridge between the Neckar and Ammer rivers.-Geography:...
, Germany) was a German physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
known for his theory of the chemical bond
Chemical bond
A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction...
(ionic bond
Ionic bond
An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal. Pure ionic bonding cannot exist: all ionic compounds have some...
/octet rule
Octet rule
The octet rule is a chemical rule of thumb that states that atoms of low The octet rule is a chemical rule of thumb that states that atoms of low The octet rule is a chemical rule of thumb that states that atoms of low (The octet rule is a chemical rule of thumb that states that atoms of low (...
), Sommerfeld–Kossel displacement law of atomic spectra, the Kossel-Stranski model for crystal growth, and the Kossel effect. Walther was the son of Albrecht Kossel
Albrecht Kossel
Ludwig Karl Martin Leonhard Albrecht Kossel was a German biochemist and pioneer in the study of genetics. He was awarded the Nobel Prize for Physiology or Medicine in 1910 for his work in determining the chemical composition of nucleic acids, the genetic substance of biological cells.Kossel...
who won the Nobel Prize in Physiology or Medicine
Nobel Prize in Physiology or Medicine
The Nobel Prize in Physiology or Medicine administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the field of life science and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, the inventor of dynamite, in his will...
in 1910.
Career
Kossel began studies at the University of Heidelberg in 1906, but was at the University of BerlinHumboldt University of Berlin
The Humboldt University of Berlin is Berlin's oldest university, founded in 1810 as the University of Berlin by the liberal Prussian educational reformer and linguist Wilhelm von Humboldt, whose university model has strongly influenced other European and Western universities...
during 1907 and 1908. In 1910, he became assistant to Philipp Lenard
Philipp Lenard
Philipp Eduard Anton von Lenard , known in Hungarian as Lénárd Fülöp Eduárd Antal, was a Hungarian - German physicist and the winner of the Nobel Prize for Physics in 1905 for his research on cathode rays and the discovery of many of their properties...
, who was also his thesis advisor. Kossel was awarded his Ph.D. in 1910, and he stayed on as assistant to Leonard until 1913.
In 1913, the year in which Niels Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...
introduced the Bohr model
Bohr model
In atomic physics, the Bohr model, introduced by Niels Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with electrostatic forces providing attraction,...
of the atom, Kossel went to the University of Munich as assistant to Arnold Sommerfeld
Arnold Sommerfeld
Arnold Johannes Wilhelm Sommerfeld was a German theoretical physicist who pioneered developments in atomic and quantum physics, and also educated and groomed a large number of students for the new era of theoretical physics...
, under whom he did his Habilitation
Habilitation
Habilitation is the highest academic qualification a scholar can achieve by his or her own pursuit in several European and Asian countries. Earned after obtaining a research doctorate, such as a PhD, habilitation requires the candidate to write a professorial thesis based on independent...
. Under Sommerfeld, Munich was a theoretical center for the developing atomic theory
Atomic theory
In chemistry and physics, atomic theory is a theory of the nature of matter, which states that matter is composed of discrete units called atoms, as opposed to the obsolete notion that matter could be divided into any arbitrarily small quantity...
, especially from the interpretation of atomic spectra. In 1916, Kossel put forth his theory of the ionic chemical bond
Ionic bond
An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal. Pure ionic bonding cannot exist: all ionic compounds have some...
(octet rule
Octet rule
The octet rule is a chemical rule of thumb that states that atoms of low The octet rule is a chemical rule of thumb that states that atoms of low The octet rule is a chemical rule of thumb that states that atoms of low (The octet rule is a chemical rule of thumb that states that atoms of low (...
), also independently advanced in the same year by Gilbert N. Lewis
Gilbert N. Lewis
Gilbert Newton Lewis was an American physical chemist known for the discovery of the covalent bond , his purification of heavy water, his reformulation of chemical thermodynamics in a mathematically rigorous manner accessible to ordinary chemists, his theory of Lewis acids and...
. In papers published in 1914, 1916, and 1920, Kossel was the first to explain the theory of absorption limits in x-ray spectra. The edge appears at a critical frequency where absorption of the radiation largely begins with the resultant ejection of photoelectrons
Photoelectric effect
In the photoelectric effect, electrons are emitted from matter as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as visible or ultraviolet light. Electrons emitted in this manner may be referred to as photoelectrons...
. In 1919, Kossel and Sommerfeld explained the similarity of the atomic spectra of neutral atoms, of atomic number
Atomic number
In chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
Z, and singly ionized atoms, of atomic number Z + 1, which became known as the Sommerfeld–Kossel displacement law. In 1920, Kossel explained another phenomenon of x-ray spectra. Under high resolution spectroscopy, the absorption edge has structure. He attributed this to absorption of radiation by electrons which are not ejected from matter as photoelectrons, but are “kicked up” to higher, unoccupied, bound electron energy levels. In early years, this was known as “Kossel structure
X-ray absorption fine structure
X-ray absorption fine structure is a specific structure observed in X-ray absorption spectroscopy . By analyzing the XAFS, information can be acquired on the local structure and on the unoccupied electronic states.-Spectra:...
.”
In 1921, Kossel took an appointment as ordinarius professor of theoretical physics at the University of Kiel
University of Kiel
The University of Kiel is a university in the city of Kiel, Germany. It was founded in 1665 as the Academia Holsatorum Chiloniensis by Christian Albert, Duke of Holstein-Gottorp and has approximately 23,000 students today...
. In 1928, he put forth his kinetic theory of crystal growth, which became known as the Kossel-Stranski model – Iwan N. Stranski independently proposed the same model.
In 1932, Kossel took the appointment as ordinarius professor of theoretical physics at the Technische Hochschule
Technische Hochschule
Technische Hochschule is what an Institute of Technology used to be called in German-speaking countries, as well as in the Netherlands, before most of them changed their name to Technische Universität or Technische Universiteit in the 1970s and in the...
at Gdańsk
Gdansk
Gdańsk is a Polish city on the Baltic coast, at the centre of the country's fourth-largest metropolitan area.The city lies on the southern edge of Gdańsk Bay , in a conurbation with the city of Gdynia, spa town of Sopot, and suburban communities, which together form a metropolitan area called the...
. During his tenure there in 1934, he discovered x-ray lattice interference of spherical waves in crystals during the bombardment of single-crystal copper with a high-energy electron beam.
In 1944, he was awarded the Max-Planck medal by the Deutsche Physikalische Gesellschaft
Deutsche Physikalische Gesellschaft
The Deutsche Physikalische Gesellschaft is the world's largest organization of physicists. The DPG's worldwide membership is cited as 60,000, as of 2011...
.
In 1945, Kossel became professor of theoretical physics and director of the Physics Institute at the University of Tübingen, where he was granted emeritus status in 1953.
Kossel died in Tübingen and is buried, as is his father, Albercht, in the Wald Friedhof, Heidelberg.
Selected bibliography
- Walther Kossel Bemerkung zur Absorption homogener Röntgenstrahlen, Verh. D. Deutsch. Phys Ges (2) 16 898-909 (1914). Received 27 September 1914, published in issue No. 20 of 30 October 1914. As cited in Mehra, Volume 1, Part 2, 2001, p. 795.
- Walther Kossel Bemerkung zur Absorption homogener Röntgenstrahlen. II, Verh. D. Deutsch. Phys Ges (2) 16 953-963 (1914). Received 23 October 1914, published in issue No. 22 of 30 November 1914. As cited in Mehra, Volume 5, Part 2, 2001, p. 919.
- Walther Kossel Bemerkung zum Seriencharakter der Röntgenstrahlen, Verh. D. Deutsch. Phys Ges (2) 18 339-359 (1916). Received 31 August 1916, published in issue No. 15-18 of 30 September 1916. As cited in Mehra, Volume 5, Part 2, 2001, p. 919.