Johannes Rydberg

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Johannes Rydberg
Rydberg, Janne (foto Per Bagge; AFs Arkiv).jpg
Johannes Rydberg
Born(1854-11-08)8 November 1854
Died28 December 1919(1919-12-28) (aged 65)
Nationality Swedish
Known for Rydberg formula
Awards Fellow of the Royal Society (1919)
Scientific career
Fields Physics
Institutions Lund University

Johannes (Janne) Robert Rydberg (Swedish:  [ˈrŷːdbærj] ; 8 November 1854 28 December 1919) was a Swedish physicist mainly known for devising the Rydberg formula, in 1888, which is used to describe the wavelengths of photons (of visible light and other electromagnetic radiation) emitted by changes in the energy level of an electron in a hydrogen atom.

Contents

Biography

Rydberg was born 8 November 1854 in Halmstad in southern Sweden, the only child of Sven Rydberg and Maria Anderson Rydberg. When he was 4 years old his father died, and the family was forced to live on a small income. In 1873 he graduated from Halmstads elementärläroverk, where he received high grades in maths and physics. Later that year he enrolled in Lund University, and two years later he was awarded his bachelor's degree. In 1879 he was awarded his Doctor of Philosophy with his dissertation "Konstruktioner af kägelsnitt i 3- och 4-punktskontakt". [1]

Rydberg began his career as an amanuensis in the institution. He became a docent in maths in 1880, and in 1882 became a docent in physics. At this time he began studying the standard atomic weight, because he wondered what was the reason for the seemingly random increase in weight for the atoms in Mendeleev's periodic system. He searched for a formula for several years to no avail. [2]

His next work was about investigating the atomic spectra, explaining why these occurred. [2] Rydberg's research was preceded by Johann Jakob Balmer's, who presented an empirical formula for the visible spectral lines of the hydrogen atom in 1885. [3] However, Rydberg's research led him to publish a formula in 1888 which could be used to describe the spectral lines not only for hydrogen but other elements as well. After his publication in 1890 on the subject, [4] Rydberg returned to his fruitless research on the periodic table. [5]

Rydberg applied for the a professorship in 1897, but despite the recommendations of experts in the subject he was rejected. However, he became an extraordinary professor instead. It wasn't until 1909 that he was upgraded into a full professorship. [6] To earn extra money he worked part-time as a numerical examiner at Sparbanken in Lund from 1891 and as an actuary in Malmö from 1905. [7]

In 1913, Rydberg became very ill and was forced to slow down his pace of research, and in 1915 he was granted leave on account of his illness. [8] He died on December 28, 1919 at Lund Hospital and was succeeded by his student Manne Siegbahn. [9] [10] Rydberg is buried at the northern cemetery in Lund and left his wife Lydia Carlsson (1856-1925), son Helge Rydberg (1887-1968) and daughter Gerda Rydberg (1891-1983).

Rydberg formula

The physical constant known as the Rydberg constant is named after him, as is the Rydberg unit. Excited atoms with very high values of the principal quantum number, represented by n in the Rydberg formula, are called Rydberg atoms. [11] Rydberg's anticipation that spectral studies could assist in a theoretical understanding of the atom and its chemical properties was justified in 1913 by the work of Niels Bohr (see hydrogen spectrum). An important spectroscopic constant based on a hypothetical atom of infinite mass is called the Rydberg (R) in his honour.

See also

Related Research Articles

Bohr model Atomic model introduced by Niels Bohr in 1913

In atomic physics, the Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System, but with attraction provided by electrostatic forces in place of gravity. After the cubical model (1902), the plum pudding model (1904), the Saturnian model (1904), and the Rutherford model (1911) came the Rutherford–Bohr model or just Bohr model for short (1913). The improvement over the 1911 Rutherford model mainly concerned the new quantum physical interpretation.

In spectroscopy, the Rydberg constant, symbol for heavy atoms or for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom. The constant first arose as an empirical fitting parameter in the Rydberg formula for the hydrogen spectral series, but Niels Bohr later showed that its value could be calculated from more fundamental constants via his Bohr model. As of 2018, and electron spin g-factor are the most accurately measured physical constants.

Rydberg formula Formula for spectral line wavelengths in alkali metals

In atomic physics, the Rydberg formula calculates the wavelengths of a spectral line in many chemical elements. The formula was primarily presented as a generalization of the Balmer series for all atomic electron transitions of hydrogen. It was first empirically stated in 1888 by the Swedish physicist Johannes Rydberg, then theoretically by Niels Bohr in 1913, who used a primitive form of quantum mechanics. The formula directly generalizes the equations used to calculate the wavelengths of the hydrogen spectral series.

Lyman-alpha line

In physics, the Lyman-alpha line, sometimes written as Ly-α line, is a spectral line of hydrogen, or more generally of one-electron ions, in the Lyman series, emitted when the electron falls from the n = 2 orbital to the n = 1 orbital, where n is the principal quantum number. In hydrogen, its wavelength of 1215.67 angstroms (121.567 nm or 1.21567×10−7 m), corresponding to a frequency of 2.47×1015 hertz, places the Lyman-alpha line in the vacuum ultraviolet part of the electromagnetic spectrum, which is absorbed by air. Lyman-alpha astronomy must therefore ordinarily be carried out by satellite-borne instruments, except for extremely distant sources whose redshifts allow the hydrogen line to penetrate the atmosphere.

Emission spectrum Frequencies of light emitted by atoms or chemical compounds

The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Therefore, spectroscopy can be used to identify elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances.

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In physics and chemistry, the Lyman series is a hydrogen spectral series of transitions and resulting ultraviolet emission lines of the hydrogen atom as an electron goes from n ≥ 2 to n = 1, the lowest energy level of the electron. The transitions are named sequentially by Greek letters: from n = 2 to n = 1 is called Lyman-alpha, 3 to 1 is Lyman-beta, 4 to 1 is Lyman-gamma, and so on. The series is named after its discoverer, Theodore Lyman. The greater the difference in the principal quantum numbers, the higher the energy of the electromagnetic emission.

Manne Siegbahn

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Rydberg may refer to:

Hydrogen spectral series Important atomic emission spectra

The emission spectrum of atomic hydrogen has been divided into a number of spectral series, with wavelengths given by the Rydberg formula. These observed spectral lines are due to the electron making transitions between two energy levels in an atom. The classification of the series by the Rydberg formula was important in the development of quantum mechanics. The spectral series are important in astronomical spectroscopy for detecting the presence of hydrogen and calculating red shifts.

The Rydberg–Ritz combination principle is an empirical generalization proposed by Walther Ritz in 1908 to describe the relationship of the spectral lines for all atoms. The principle states that the spectral lines of any element include frequencies that are either the sum or the difference of the frequencies of two other lines. Lines of the spectra of elements could be predicted from existing lines. Since the frequency of light is proportional to the wavenumber or reciprocal wavelength, the principle can also be expressed in terms of wavenumbers which are the sum or difference of wavenumbers of two other lines.

Bengt Edlén

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Anders Jonas Ångström Swedish physicist

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History of spectroscopy

The history of spectroscopy began in the 17th century. New designs in optics, specifically prisms, enabled systematic observations of the solar spectrum. Isaac Newton first applied the word spectrum to describe the rainbow of colors that combine to form white light. During the early 1800s, Joseph von Fraunhofer conducted experiments with dispersive spectrometers that enabled spectroscopy to become a more precise and quantitative scientific technique. Since then, spectroscopy has played and continues to play a significant role in chemistry, physics and astronomy. Fraunhofer observed and measured dark lines in the Sun's spectrum, which now bear his name although several of them were observed earlier by Wollaston.

Sten von Friesen was a Swedish physicist who was most known for having participated in the Swedish hit show Fråga Lund.

Hermann Grimmeiss, is a German-Swedish physicist. He became the first professor of solid-state physics at Lund University in 1965, and he held his post until his retirement in 1996. He became an important part of the Department of Physics and focused his research on electrical and photoelectric studies of semiconductor defects.

Hans Ryde is a Swedish physicist who is a member of the Royal Swedish Academy of Sciences. He was awarded his Doctor of Philosophy at Stockholm University in 1962. He was employed by the Research Institute of Atomic Physics in Frecati, Stochholm during the 60s and 70s, where he did his research in the field of nuclear structural physics in general and deformed nuclear nuclei in particular. By using a 225-cm cyclotron he discovered that there was a backbending effect in fast rotating nuclei. In 1975 he replaced Sten von Friesen as a professor at the Department of Physics, Lund University. He became a member of the Royal Swedish Academy of Sciences in 1992 and the Finnish Society of Sciences and Letters in 1988.

References

  1. Hamilton, Paul Charles (1992). Janne Rydberg: a physicist in 19th-century Sweden. [Cambridge, Massachusetts]. pp. 26–30.
  2. 1 2 Litzén, Ulf (2015). Fysik i Lund under 300 år (in Swedish). Lund: Lunds universitetshistoriska sällskap. pp. 71–75. ISBN   9789175453200.
  3. Magie, William Francis (1969). A Source Book in Physics. Cambridge, Massachusetts: Harvard University Press. p 360
  4. See:
  5. Litzén (2015). Fysik i Lund under 300 år (in Swedish). p. 96.
  6. Leide, Arvid (1954). "Janne Rydberg och hans kamp för professuren".Cite journal requires |journal= (help)
  7. Hamilton (1992). Janne Rydberg: a physicist in 19th-century Sweden. p. 46.
  8. Litzén (2015). Fysik i Lund under 300 år (in Swedish). p. 84.
  9. Hamilton (1992). Janne Rydberg: a physicist in 19th-century Sweden. pp. 47–48.
  10. Martinson, I.; Curtis, L.J. (2005). "Janne Rydberg – his life and work" (PDF). Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 235 (1–4): 17–22. Bibcode:2005NIMPB.235...17M. doi:10.1016/j.nimb.2005.03.137.
  11. Šibalić, Nikola; S Adams, Charles (2018). Rydberg Physics. IOP Publishing. Bibcode:2018ryph.book.....S. doi:10.1088/978-0-7503-1635-4. ISBN   9780750316354.