Johannes (Janne) Robert Rydberg (; 8 November 1854 – 28 December 1919) was a Swedish

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

mainly known for devising the

Rydberg formula 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 ...

, in 1888, which is used to describe the

wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...

s of

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless particles that can ...

s (of

visible light Light, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm ...

and other

electromagnetic radiation In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...

) emitted by changes in the energy level of an

electron The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up qua ...

in a

hydrogen atom A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb for ...

Biography

Rydberg was born 8 November 1854 in

Halmstad Halmstad () is a port, university, industrial and recreational urban areas of Sweden, city at the mouth of the Nissan (river), Nissan river, in the provinces of Sweden, province of Halland on the Sweden, Swedish west coast. Halmstad is the seat ...

in southern

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

, 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 Lund University () is a Public university, public research university in Sweden and one of Northern Europe's oldest universities. The university is located in the city of Lund in the Swedish province of Scania. The university was officially foun ...

, and two years later he was awarded his

bachelor's degree A bachelor's degree (from Medieval Latin ''baccalaureus'') or baccalaureate (from Modern Latin ''baccalaureatus'') is an undergraduate degree awarded by colleges and universities upon completion of a course of study lasting three to six years ...

. In 1879 he was awarded his

Doctor of Philosophy A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of Postgraduate education, graduate study and original resear ...

with his dissertation "Konstruktioner af kägelsnitt i 3- och 4-punktskontakt". Delegates to the Fourth Conference International Union for Cooperation in Solar Research at Mount Wilson Observatory

Delegates to the Fourth Conference International Union for Cooperation in Solar Research at Mount Wilson Observatory

Rydberg began his career as an

amanuensis An amanuensis ( ) ( ) or scribe is a person employed to write or type what another dictates or to copy what has been written by another. It may also be a person who signs a document on behalf of another under the latter's authority. In some aca ...

in the institution. He became a

docent The term "docent" is derived from the Latin word , which is the third-person plural present active indicative of ('to teach, to lecture'). Becoming a docent is often referred to as habilitation or doctor of science and is an academic qualifi ...

in maths in 1880, and in 1882 became a docent in physics. At this time he began studying the

standard atomic weight The standard atomic weight of a chemical element (symbol ''A''r°(E) for element "E") is the weighted arithmetic mean of the relative isotopic masses of all isotopes of that element weighted by each isotope's abundance on Earth. For example, ...

, 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. His next work was about investigating the atomic spectra, explaining why these occurred. Rydberg's research was preceded by Johann Jakob Balmer's, who presented an

empirical Empirical evidence is evidence obtained through sense experience or experimental procedure. It is of central importance to the sciences and plays a role in various other fields, like epistemology and law. There is no general agreement on how t ...

formula for the visible

spectral line A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission (electromagnetic radiation), emission or absorption (electromagnetic radiation), absorption of light in a narrow frequency ...

s of the

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

atom in 1885. 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, Rydberg returned to his fruitless research on the periodic table. Rydberg applied for a professorship in 1897, but despite the recommendations of experts in the subject he was rejected. However, he became an extraordinary professor instead. It was not until 1909 that he was upgraded into a full professorship. 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. 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. He died on 28 December 1919 at Lund Hospital and was succeeded by his student Manne Siegbahn. 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 A physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that cannot be explained by a theory and therefore must be measured experimentally. It is distinct from a mathematical constant, which has a ...

known as the

Rydberg constant In spectroscopy, the Rydberg constant, symbol R_\infty for heavy atoms or R_\text for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom. The constant first ...

is named after him, as is the Rydberg unit. Excited atoms with very high values of the

principal quantum number In quantum mechanics, the principal quantum number (''n'') of an electron in an atom indicates which electron shell or energy level it is in. Its values are natural numbers (1, 2, 3, ...). Hydrogen and Helium, at their lowest energies, have just ...

, represented by ''n'' in the

, are called Rydberg atoms. 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 Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the No ...

(see

hydrogen spectrum 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 atomic electron transition, transitions b ...

). An important spectroscopic constant based on a hypothetical atom of infinite mass is called the Rydberg (R) in his honour.

References

External links

* * {{DEFAULTSORT:Rydberg, Johannes 1854 births 1919 deaths Swedish physicists Optical physicists People connected to Lund University Lund University alumni Spectroscopists People involved with the periodic table Foreign members of the Royal Society People from Halmstad

Biography

Rydberg formula

See also

References

External links