# Johannes Rydberg

> Swedish physicist

**Wikidata**: [Q311567](https://www.wikidata.org/wiki/Q311567)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Johannes_Rydberg)  
**Source**: https://4ort.xyz/entity/johannes-rydberg

## Summary
Johannes Rydberg was a Swedish physicist, university teacher, and mathematician known for his foundational research in physics. He is primarily recognized for the Rydberg formula, which calculates spectral line wavelengths, and the Rydberg constant, a fundamental physical constant. His work significantly advanced the understanding of atomic structure, energy, and matter.

## Biography
- Born: [Date and place not provided in source material]
- Nationality: Sweden
- Education: [Degrees and institutions not provided in source material]
- Known for: Rydberg formula, Rydberg constant, Rydberg atom, Rydberg matter, Rydberg–Ritz combination principle
- Employer(s): Lund University
- Field(s): Physics, Mathematics

## Contributions
Johannes Rydberg's work encompasses several fundamental discoveries and formulas in the field of physics. He developed the **Rydberg formula**, a mathematical expression used to determine the wavelengths of spectral lines in alkali metals. He defined the **Rydberg constant**, which serves as a crucial physical constant in atomic physics. His research also led to the conceptualization of the **Rydberg atom**, an excited atomic quantum state characterized by a high principal quantum number (n). Furthermore, he is associated with **Rydberg matter**, an exotic phase of matter formed by Rydberg atoms, and the **Rydberg–Ritz combination principle**, a principle governing spectral lines.

## FAQs
**Who is Johannes Rydberg?**
Johannes Rydberg was a Swedish physicist, university teacher, and mathematician who made significant contributions to the understanding of atomic physics and spectral lines.

**What is the Rydberg formula?**
The Rydberg formula is a formula for spectral line wavelengths in alkali metals, developed by Johannes Rydberg to predict the wavelengths of light emitted by chemical elements.

**Where did Johannes Rydberg work?**
He was affiliated with Lund University, a university located in the city of Lund in the province of Scania, Sweden.

**What are Rydberg atoms and Rydberg matter?**
A Rydberg atom is an excited atomic quantum state with a high principal quantum number (n), while Rydberg matter is an exotic phase of matter formed by these Rydberg atoms.

**What are the aliases of Johannes Rydberg?**
He is also known as Janne Rydberg and Johannes Robert Rydberg.

## Why They Matter
Johannes Rydberg's work provided critical tools for understanding atomic spectra and the behavior of electrons in atoms. The Rydberg formula and constant remain essential in spectroscopy and quantum mechanics, allowing scientists to calculate energy levels and transitions with precision. His concepts regarding Rydberg atoms and matter have influenced modern research in exotic states of matter. Additionally, the naming of a lunar impact crater, "Rydberg," in his honor signifies his lasting impact on the scientific community.

## Notable For
- Development of the Rydberg formula for spectral line wavelengths in alkali metals.
- Definition of the Rydberg constant, a fundamental physical constant.
- Conceptualization of the Rydberg atom (excited atomic quantum state with high principal quantum number).
- Identification of Rydberg matter (an exotic phase of matter formed by Rydberg atoms).
- Contribution to the Rydberg–Ritz combination principle regarding spectral lines.
- Having a lunar impact crater named "Rydberg" in his honor.

## Body
### Professional Identity
Johannes Rydberg, also known by the aliases Janne Rydberg and Johannes Robert Rydberg, was a human from Sweden. As a scientist, he held multiple professional roles, including that of a physicist, defined as a scientist who does research in physics. He was also a university teacher, a person teaching at a university or college, and a mathematician, characterized as a person with extensive knowledge of mathematics. His work was centered on physics, the study of matter and its motion, along with related concepts such as energy and force.

### Institutional Affiliations
Rydberg was affiliated with Lund University, an institution located in the city of Lund in the province of Scania, Sweden. The university, which was established on December 19, 1666, served as his base for academic and research activities. His work is also contextually related to the Royal Society, an English learned society for science that was established on November 1, 1660, and is headquartered in London.

### Scientific Contributions and Concepts
Rydberg's contributions to physics are anchored in his development of specific formulas and constants that describe atomic behavior.
*   **Rydberg Formula:** He created the Rydberg formula, which is a formula for spectral line wavelengths in alkali metals. This mathematical tool is vital for analyzing the emission spectra of chemical elements.
*   **Rydberg Constant:** He established the Rydberg constant, a physical constant that appears in the formula describing the wavelengths of spectral lines.
*   **Rydberg Atom:** His research includes the concept of the Rydberg atom, defined as an excited atomic quantum state with a high principal quantum number (n).
*   **Rydberg Matter:** He is associated with the discovery or description of Rydberg matter, an exotic phase of matter formed by Rydberg atoms.
*   **Rydberg–Ritz Combination Principle:** He contributed to the understanding of spectral lines through the Rydberg–Ritz combination principle, a principle of spectral lines.

### Legacy and Recognition
The impact of Johannes Rydberg's work is immortalized in both scientific terminology and off-world geographic features. A lunar impact crater is named "Rydberg" in his honor. His name is permanently attached to the fundamental constants and states of matter he studied, ensuring that his contributions to the fields of physics and mathematics continue to be recognized in scientific discourse.

## References

1. Great Soviet Encyclopedia (1969–1978)
2. MacTutor History of Mathematics archive
3. Integrated Authority File
4. [Source](https://www.svenskagravar.se/search?query=Rydberg+Johannes+Robert&parishId=&cemeteryId=&graveNumber=&birthDate=&deathDate=&burialDate=)
5. Find a Grave
6. Complete List of Royal Society Fellows 1660-2007
7. International Standard Name Identifier
8. CiNii Research
9. Virtual International Authority File
10. Johannes (Janne) R Rydberg. Dictionary of Swedish National Biography
11. SNAC
12. Brockhaus Enzyklopädie
13. Croatian Encyclopedia
14. Freebase Data Dumps. 2013
15. nobelprize.org
16. IdRef
17. LIBRIS. 2012