ARNOLD SOMMERFELD: BIOGRAPHY, ATOMIC MODEL, CONTRIBUTIONS - ARTE - 2025

Arnold Sommerfeld (1868-1951) was a German physicist, best known for having developed atomic theory with Bohr more than a century ago. He was one of the founders of theoretical physics, which became an independent discipline thanks to his contributions, along with the works of Max Planck, Albert Einstein and Niels Nohr. He is considered a pioneer of quantum and atomic physics.

Today the Bohr-Sommerfeld atom and the fine structure constant are still concepts used by physicists. Some scholars have associated Sommerfeld's name with the first modern school of theoretical physics. His contributions were also reflected in the textbook Atomic structure and spectral lines, very important in atomic physics.

Source: GFHund, via wikimedia commons.

This book of his authorship spread around the world, was translated into multiple languages ​​and was a pillar in the training of many students in the field of nuclear physics.

Biography

His full name was Arnold Johannes Wilhelm Sommerfeld. The German physicist was born on December 5, 1868 in Königsberg, Germany.

His parents were Cäcile Matthias and Franz Sommerfeld, a doctor of the time. The couple had more children: Walter, born in 1863, was Arnold's older brother, who also had a sister. Margarethe was two years younger than Arnold but only lived for 10 years as she was affected by scarlet fever.

From very early on, Arnold showed a lot of interest in the arts and was even very talented.

Studies

His interest in the arts was reflected in the studies he carried out in his hometown of Königsberg. He showed a special passion for literature, particularly for the classic works of German authors. He did not have grades that were outstanding in all subjects, although he was not a bad student either.

Before starting college, the idea that went around his head was to dedicate himself to the construction industry, an area in which a member of his family had already worked.

The only problem that Sommerfeld found was that in order to work in the area of ​​civil engineering, he would have to have left his hometown and settled in a city that had a technical university where studies were taught that would serve him for his career.

At the Albert University of Königsberg, named after its founder, he could not study engineering. But since he was not very sure about the career he wanted to choose, the move took a back seat and he preferred to stay close to his family.

University stage

During the first semester he oriented himself on the courses taught at the institution. He signed up for courses on economics, economic policy, ethnography, political parties, calculus, German civil law, criticism of Kant, and fundamentals of ethics.

After finishing that first semester, Sommerfeld began to focus his curriculum on courses that had a more technical base, but he continued without focusing on the area of ​​physics. Actually his main interest was in the area of ​​mathematics.

He spent six years in college, earned a Ph.D., and gained the confidence to face his future. Among his professors he counted personalities such as Ferdinand von Lindemann, Adolf Hurwitz, David Hilbert and the also physicist Emil Wiechert.

Military stage

After completing his university studies, Sommerfeld fulfilled his obligations in the military area as a volunteer for one year. He was part of the infantry regiment at Königsberg, although it was not a job he greatly enjoyed; he considered the military work of a soldier as something tedious.

One of the advantages of having trained for the infantry regiment was that it was in Königsberg and therefore stayed close to home. Even due to the voluntary nature of his work, he could sleep at home.

Race

After completing his obligations in the military world and after obtaining a doctorate, he moved to Göttingen in 1891 to work at the University of that city. In Göttingen he worked teaching some classes in mathematics and theoretical physics. He also served as an assistant to Felix Klein, a well-known mathematician of the time.

By 1897 he went to Clausthal Zellerfeld University, in Goslar, where he also taught for three years before moving to Aachen. At the city's university he served as a professor of technical engineering.

Being a professor of theoretical physics in Munich, between 1906 and 1931, it was when he completed his most relevant works. He came to Munich to replace the physicist Ludwig Boltzmann as professor of theoretical physics. In addition he was in charge of the direction of the Institute of Theoretical Education that was in Munich in the University of the state.

Death

Arnold Sommerfeld died on April 26, 1951. His death occurred in Munich, where he suffered a traffic accident while walking with his grandchildren.

At the end of March, the German physicist was walking around his home in Munich with his grandchildren, when he was hit by a car. After ten days he lost consciousness and shortly after he died as a result of the injuries he suffered as a result of the accident.

Atomic models

His main work occurred in 1915 when, together with the Danish physicist Niels Bohr, he was in charge of transforming some aspects of atomic theory. For this, both scientists relied on other theories, such as quantum and relativistic.

His motivation was based on the fact that atomic theory had flaws when it came to explaining what complex atoms were

In the ideas that Sommerfeld and Bohr raised, they explained that the orbits made by electrons were elliptical in shape. In addition, these orbits had another quantum number, considered secondary.

The importance of these quantum numbers, both the secondary and the main one that Bohr obtained, was that he determined whether the electron had an angular momentum. This was relevant because it allowed us to determine if the electron had kinetic energy.

He also talked about the presence of a third quantum number, which was called magnetic. This number had the function of establishing how inclined the plane of the orbit was.

By 1916, the German physicist Friedrich Paschen showed that Sommerfeld's ideas were correct, but it was still not a definitive theory since it did not solve some problems

problems

The periodic system of the elements and the behavior at the chemical level that they had had a better explanation thanks to the atomic model called Bohr-Sommerfeld. But the contribution of other studies was also necessary for this. For example, it benefited from subsequent discoveries.

Like Wolfgang Pauli, in 1924, who stated that the presence of two electrons could not occur at the same time if they had the same quantum number. Furthermore, a fourth quantum number was introduced in 1924 thanks to the advances of Goudsmit and Unlenbeck.

It was the ideas of wave quantum mechanics that allowed for better analysis of spectra. Finally, this Bohr-Sommerfeld model was later replaced by a model that relied on wave mechanics.

Other contributions

Sommerfeld's work allowed him to develop more ideas in the field. Of his applications of the theory to technical problems, the theory he developed of lubricant friction and his contributions to wireless telegraphy were the best known.

His contributions in other fields were also relevant, especially when he worked on the classical theory of electromagnetism.

His work as a teacher was also a great contribution to the scientific world. From 1906, when he arrived at the University of Munich, he trained several generations of theoretical physicists. His students include eight Nobel laureates.

It was important for introducing the second and third quantum numbers, but also the theory of the X-ray wave.

During the last stage of his career, the German was in charge of using statistical mechanics to explain some behaviors. Specifically, he explained the electronic properties that metals had.

He played a prominent role in establishing the Journal of Physics in 1920. This publication served to publish and review many works in the area of ​​physics.

Published works

Sommerfeld published several works throughout his career. Two of his works were the most outstanding, as is the case of Atoms and spectral lines and the text of Introduction to theoretical physics.

In total, there were more than 10 books that were authored, some of them have several volumes. In addition to the many articles he wrote about his ideas and discoveries.

Nobel Prizes

Sommerfeld is the protagonist of one of the most curious cases in the scientific world. Despite all the contributions he made, he was never awarded a Nobel Prize in physics.

It is even more curious if you take into account that he is the physicist with the most nominations in the history of the Nobel Prize. It has a total of 84 candidacies, which were accumulated between the years 1917 and 1951.

Only in 1929 he had nine nominations. And the year he died he received four more.

Although he never received the Award, he has the honor of being the physicist with the most winning students.

References

1. Arnold Sommerfeld - German physicist. Recovered from britannica.com
2. Beléndez, A. (2017). Sommerfeld: the Eternal Nobel Candidate. Recovered from bbvaopenmind.com
3. Eckert, M. (2013). Arnold Sommerfeld. New York, NY: Springer.
4. Izquierdo Sañudo, M. (2013). Historical evolution of the principles of chemistry.: Uned - National University.
5. Seth, S. (2010). Crafting the quantum. Cambridge, Mass.: MIT Press.