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Atomic Physics Timeline

Records in the Physics collection relating to atomic structure, atomic theory, electron shells, spectra and spectroscopy.

90 records1838–2021

About this Atomic Physics timeline

Explore atomic structure, electron behaviour, spectra, isotopes and experiments that established the modern physical picture of the atom.

This page contains 90 records spanning 1838–2021. Frequently represented countries include Great Britain, Sweden, United States of America, Germany, Denmark. Example event labels include Discovery of Electrons, Atomic Spectral Series, Rydberg Formula, Zeeman Effect and Charged Oscillators, Cathode-Ray Charge-to-Mass Measurement.

Physicists frequently represented in these records

Enrico Fermi6 matching records Erwin Rudolf Josef Alexander Schrodinger6 matching records Niels Henrik David Bohr4 matching records Manne Georg Siegbahn4 matching records Kai Manne Borje Siegbahn4 matching records Henry Gwyn Jeffreys Moseley3 matching records

Timeline records

Date	Person	Event	Place	Description
1838	Richard Laming	Discovery of Electrons	Great Britain	Between 1838 and 1851, British natural philosopher Richard Laming developed the idea that an atom is composed of a core of matter surrounded by subatomic particles that had unit electric charge
1881	Hermann von Helmholtz	Discovery of Electrons	Germany	In 1881, German physicist Hermann von Helmholtz argued that both positive and negative charges were divided into elementary parts, each of which "behaves like atoms of electricity"
1888	Johannes Robert Rydberg Physicist	Atomic Spectral Series	Lund, Sweden	Provides a mathematical basis for interpreting hydrogen spectral lines.
1888	Johannes Robert Rydberg Physicist	Rydberg Formula	Lund, Sweden	Develops a formula describing regular patterns in atomic spectra.
1896	Pieter Zeeman Physicist	Zeeman Effect and Charged Oscillators	Leiden, Netherlands	Finds that magnetic fields split spectral lines, providing evidence for charged particles participating in atomic radiation.
1897	Emil Wiechert Physicist	Cathode-Ray Charge-to-Mass Measurement	Konigsberg, Germany	Obtains an early charge-to-mass estimate for cathode-ray particles, supporting their subatomic character.
1904	Joseph John Thomson Physicist	Electron Atomic Model	Cambridge, Great Britain	Proposes an atomic model containing negatively charged electrons embedded within diffuse positive charge.
1912	William Lawrence Bragg Physicist	X-Ray Crystal Diffraction	Cambridge, Great Britain	Connects diffraction angles with atomic plane spacing.
1913	Niels Henrik David Bohr Theoretical Physicist	Bohr Atomic Model	Copenhagen, Denmark	Publishes an atomic model with electrons occupying discrete energy states.
1913	William Lawrence Bragg Physicist	Sodium Chloride Crystal Structure	Cambridge, Great Britain	Determines the arrangement of atoms within sodium chloride crystals.
1913	Henry Moseley Physicist	Atomic Number	Manchester, Great Britain	Establishes atomic number, placing uranium at 92.
1913	Henry Gwyn Jeffreys Moseley Physicist	Atomic Number Ordering	Oxford, Great Britain	Shows that elements should be ordered by atomic number rather than atomic weight, providing the physical basis of the modern periodic table.
1913	Henry Gwyn Jeffreys Moseley Physicist	Missing Atomic Numbers Identified	Oxford, Great Britain	Uses X-ray spectra to identify gaps in the sequence of atomic numbers and demonstrates that specific elements remain undiscovered.
1913	Joseph John Thomson Physicist	Neon Isotopes	Cambridge, Great Britain	Finds evidence that neon atoms occur with different masses.
1914	James Franck Physicist	Quantized Electron Collision Energy	Berlin, Germany	With Gustav Hertz, shows that electrons transfer energy to mercury atoms in discrete amounts, confirming quantized atomic excitation.
1914	Henry Moseley	Discovery of Atomic Numbers	Great Britain	Studies X-rays emitted by metals. Makes sense of the periodic table by stating elements can only have integral numbers
1914	Henry Gwyn Jeffreys Moseley Physicist	Periodic Table Anomalies Resolved	Oxford, Great Britain	Explains why elements such as tellurium and iodine must be ordered contrary to atomic weight by showing that atomic number is the fundamental organising principle.
1916	Manne Georg Siegbahn Experimental Physicist	Characteristic X-Ray Measurement	Lund, Sweden	Advances understanding of atomic electron shells through high-resolution spectroscopy.
1916	Manne Georg Siegbahn Experimental Physicist	Precision X-Ray Spectroscopy	Lund, Sweden	Develops improved instruments for precise measurement of X-ray spectra.
1919	Ernest Rutherford Physicist	Proton as Nuclear Charge Carrier	Cambridge, Great Britain	Identifies the hydrogen nucleus as a fundamental positive particle, helping connect atomic number with the positive charge of the atomic nucleus.
3 June 1920	Ernest Rutherford Physicist	Neutral Nuclear Particle Proposal	Cambridge, New Zealand	Suggests that a neutral proton-electron combination could exist inside atomic nuclei, anticipating the neutron.
3 March 1921	Niels Henrik David Bohr Theoretical Physicist	Copenhagen Physics Institute Opened	Copenhagen, Denmark	Creates an international centre for atomic and quantum research.
10 December 1922	Niels Henrik David Bohr Theoretical Physicist	Atomic Structure Recognition	Stockholm, Denmark	Gains recognition for applying quantum ideas to the structure of atoms.
10 December 1922	Niels Henrik David Bohr Theoretical Physicist	Nobel Prize in Physics	Stockholm, Denmark	Receives the physics prize for research on atomic structure and radiation.
1922	Niels Bohr Physicist	Nobel Prize	Stockholm, Denmark	Receives the Nobel Prize in Physics for investigations of atomic structure and the radiation emitted by atoms.
1923	Enrico Fermi Physicist	Quantum Theory Studies	Göttingen, Italy	Studies emerging quantum theory in Göttingen and deepens his familiarity with the mathematical methods being applied to atomic physics.
1923	Erwin Rudolf Josef Alexander Schrodinger Professor	Atomic Spectra Research	Zurich, Austria	Investigates problems in atomic spectra as his attention increasingly shifts toward unresolved questions in quantum theory.
10 December 1924	Manne Georg Siegbahn Experimental Physicist	Nobel Prize in Physics	Stockholm, Sweden	Receives the physics prize for discoveries in X-ray spectroscopy.
10 December 1924	Manne Georg Siegbahn Experimental Physicist	X-Ray Spectroscopy Recognition	Stockholm, Sweden	Is recognized for highly accurate methods mapping characteristic X-ray spectra.
1924	Karl Manne Georg Siegbahn	Nobel Prize	Stockholm, Sweden	Receives the Nobel Prize in Physics for discoveries and research in X-ray spectroscopy.
1925	Pierre Victor Auger Physicist	Auger Electron Effect	Paris, France	Identifies radiationless atomic relaxation in which energy ejects a secondary electron, now called an Auger electron.
1925	Albert Einstein Physicist	Second Quantum Gas Paper	Berlin, Germany	Publishes further work on the quantum theory of the ideal monatomic gas.
1925	Wolfgang Ernst Pauli Theoretical Physicist	Electron State Restriction	Hamburg, Austria	Explains atomic shell structure through a fundamental quantum restriction.
1925	Erwin Rudolf Josef Alexander Schrodinger Professor	de Broglie Matter Waves Influence	Zurich, Austria	Studies Louis de Broglie's matter-wave ideas and recognizes that they may provide a new route to understanding atomic structure.
1 December 1926	Erwin Rudolf Josef Alexander Schrodinger Professor	Undulatory Theory Physical Review Paper	Zurich, Austria	Publishes an English-language account of wave mechanics in Physical Review under the title An Undulatory Theory of the Mechanics of Atoms and Molecules.
1926	Albert Einstein Physicist	Rupp Radiation Experiments	Berlin, Germany	Collaborates with Emil Rupp on proposed tests of whether atomic radiation behaves as waves or quanta.
1926	Erwin Schrodinger Physicist	Wave Equation for Atomic Electrons	Zurich, Austria	Formulates wave mechanics in which electron states in atoms are represented by wavefunctions obeying the Schrodinger equation.
1926	Erwin Rudolf Josef Alexander Schrodinger Professor	Hydrogen Spectrum Wave Mechanics	Zurich, Austria	Uses the new wave equation to derive the allowed energy levels of the hydrogen atom from an eigenvalue problem rather than prescribed electron orbits.
1927	Enrico Fermi Professor	Thomas-Fermi Atomic Model	Rome, Italy	Develops the statistical Thomas-Fermi model for estimating the distribution of electrons in many-electron atoms.
1928	Enrico Fermi Professor	Introduction to Atomic Physics Teaching	Rome, Italy	Expands advanced teaching in atomic and theoretical physics at Rome and trains a generation of Italian physicists in modern quantum methods.
1928	Werner Heisenberg Physicist	Quantum Theory Research	Leipzig, Germany	Develops applications of quantum mechanics to atomic, molecular and solid-state physics in Leipzig.
1930	Nevill Francis Mott Physicist	Relativistic Electron Scattering	Cambridge, Great Britain	Develops a quantum treatment of electron scattering by atoms that includes electron spin and relativistic effects.
1931	Enrico Fermi Professor	Rome Nuclear Physics Shift	Rome, Italy	Begins shifting the focus of his research group from atomic spectroscopy toward the emerging problems of nuclear physics.
1932	James Chadwick Physicist	Discovery of Neutron	Cambridge, Great Britain	Discovers the neutron, clarifying nuclear structure and explaining how isotopes of the same element can share an atomic number while differing in mass.
1932	Werner Heisenberg Physicist	Proton-Neutron Nuclear Model	Leipzig, Germany	Develops a nuclear model treating protons and neutrons as the principal constituents of atomic nuclei.
1932	Dmitri Ivanenko Physicist	Nuclear Proton-Neutron Model	Leningrad, Russia	Proposes that atomic nuclei are composed of protons and neutrons rather than nuclear electrons.
12 September 1933	Leo Szilard Physicist	Neutron Chain Reaction Concept	London, Hungary	Conceives a neutron-driven nuclear chain reaction after reading about Rutherford comments on atomic energy.
December 1933	Paul Adrien Maurice Dirac Physicist	Nobel Prize for Quantum Electron Theory	Stockholm, Great Britain	Shares the Nobel Prize in Physics for new forms of atomic theory that include relativistic electron states.
1933	Paul Adrien Maurice Dirac Physicist	Nobel Prize	Stockholm, Great Britain	Shares the Nobel Prize in Physics for developing new productive forms of atomic theory, including a relativistic quantum theory of the electron.
1933	Erwin Rudolf Josef Alexander Schrodinger	Nobel Prize	Stockholm, Austria	Shares the Nobel Prize in Physics for discoveries in atomic theory and quantum mechanics.
1933	Erwin Rudolf Josef Alexander Schrodinger Nobel Laureate	Nobel Prize Shared with Paul Dirac	Stockholm, Austria	Shares the 1933 Nobel Prize in Physics with Paul Dirac for the discovery of new productive forms of atomic theory.
1935	James Chadwick Physicist	Nobel Prize	Stockholm, Great Britain	Receives the Nobel Prize in Physics for discovering the neutron, a neutral nuclear particle fundamental to understanding atomic nuclei.
May 1942	Robert Oppenheimer	Manhattan Project	United States of America	Oppenheimer is given the title "Coordinator of Rapid Rupture", specifically referring to the propagation of a fast neutron chain reaction in an atomic bomb
1943	Mark Oliphant Physicist	Manhattan Project	Birmingham, Great Britain	Moves from Birmingham nuclear research into Allied atomic bomb work.
1943	Julius Robert Oppenheimer	Manhattan Project	Los Alamos, United States of America	Appointed head of the Manhattan Project by Roosevelt to develop the atomic bomb
8 December 1944	Joseph Rotblat	Manhattan Project Resignation	Los Alamos, Poland	Rotblat leaves the Manhattan Project after concluding that Germany is no longer developing an atomic bomb threat requiring his participation.
1944	Enrico Fermi Physicist	Move to Los Alamos	Los Alamos, United States of America	Moves to Los Alamos and joins the laboratory effort to solve scientific problems associated with designing the first atomic weapons.
1944	Isidor Isaac Rabi	Nobel Prize	Stockholm, United States of America	Receives the Nobel Prize in Physics for the resonance method used to measure magnetic properties of atomic nuclei.
11 June 1945	James Franck	Franck Report	Chicago, Germany	Franck's committee issues a report urging international control of atomic energy and recommending a demonstration before combat use.
12 August 1945	Henry DeWolf Smyth	Manhattan Project	United States of America	The Smyth Report was the common name given to an administrative history written by physicist Henry DeWolf Smyth about the Allied World War II effort to develop the atomic bomb, the Manhattan Project
12 August 1945	Henry DeWolf Smyth	Smyth Report	United States of America	The Smyth Report was the common name given to an administrative history written by physicist Henry DeWolf Smyth about the Allied World War II effort to develop the atomic bomb, the Manhattan Project
12 August 1945	Harry S Truman President of USA	Smyth Report	United States of America	The Smyth Report is released to the public, giving the first technical history of the development of the first atomic bombs
1945	Enrico Fermi Physicist	Interim Committee Scientific Panel	Washington, United States of America	Serves on the scientific panel advising the Interim Committee on issues concerning the wartime use and postwar implications of atomic energy.
1946	Frederic Joliot-Curie Physicist	Atomic Energy Commission	Paris, France	Becomes high commissioner of the French atomic energy authority.
29 August 1949	Igor Vasilyevich Kurchatov Nuclear Physicist	First Soviet Atomic Test	Semipalatinsk, Russia	Directs the scientific programme producing the first Soviet atomic bomb test.
1950	Alfred Kastler Physicist	Atomic Energy-Level Control	Paris, France	Creates a method enabling precise spectroscopy and later laser development.
1950	Alfred Kastler Physicist	Optical Pumping	Paris, France	Proposes using light to redistribute atoms among quantum energy states.
1952	Isidor Isaac Rabi Chairman of AEC	Atomic Energy Commission	Austria	Appointed Chairman of the Atomic Energy Commissions General Advisery Committee
January 1955	Bertram Brockhouse Physicist	Triple-Axis Neutron Results	Chalk River, Canada	Presents early triple-axis neutron spectroscopy results after NRX returns to operation.
1956	Homi Jehangir Bhabha Chairman · Atomic Energy Commission	Apsara Reactor	Trombay, India	Homi Bhabha leads India's atomic energy programme when Apsara, Asia's first research reactor, reaches criticality.
1957	Kai Manne Borje Siegbahn Experimental Physicist	Electron Spectroscopy for Chemical Analysis	Uppsala, Sweden	Develops methods for accurately measuring electron energies emitted from matter.
1957	Kai Manne Borje Siegbahn Experimental Physicist	High-Resolution Photoelectron Spectroscopy	Uppsala, Sweden	Creates high-resolution spectroscopy for studying atomic and molecular electronic structure.
1958	Bertram Brockhouse Physicist	Constant-Q Neutron Spectroscopy	Chalk River, Canada	Develops the constant-Q method for measuring excitations with neutron spectroscopy.
1960	Homi Jehangir Bhabha Chairman · Atomic Energy Commission	CIRUS Reactor	Trombay, India	Under Homi Bhabha's leadership, the CIRUS research reactor becomes operational at Trombay and expands India's nuclear research capacity.
10 December 1975	Aage Niels Bohr Nuclear Physicist	Nobel Prize in Physics	Stockholm, Denmark	Shares the physics prize for describing collective motion in atomic nuclei.
10 December 1981	Kai Manne Borje Siegbahn Experimental Physicist	Electron Spectroscopy Recognition	Stockholm, Sweden	Receives recognition for methods revealing atomic and molecular energy levels.
10 December 1981	Kai Manne Borje Siegbahn Experimental Physicist	Nobel Prize in Physics	Stockholm, Sweden	Shares the physics prize for high-resolution electron spectroscopy.
1989	Hans Dehmelt	Nobel Prize	Stockholm, United States of America	Shares the Nobel Prize in Physics for developing the ion trap technique used in high-precision spectroscopy.
1989	Norman Ramsey	Nobel Prize	Stockholm, United States of America	Shares the Nobel Prize in Physics for the separated oscillatory fields method and its use in atomic precision measurements.
1993	Donald Eigler Physicist	Quantum Corral Electron Standing Waves	San Jose, United States of America	Builds a ring of atoms with a scanning tunnelling microscope and images standing-wave patterns of surface electrons confined inside it.
December 1994	Bertram Brockhouse Physicist	Nobel Prize for Neutron Spectroscopy	Stockholm, Canada	Shares the Nobel Prize in Physics for developing neutron spectroscopy.
1994	Sigurd Hofmann Physicist	Discovery of Darmstadtium	Darmstadt, Germany	Leads a team that produces element 110, later named darmstadtium, by fusing heavy atomic nuclei at the GSI laboratory.
1999	Lene Vestergaard Hau Physicist	Slow Light Experiment	Cambridge Massachusetts, Denmark	Leads an experiment slowing light dramatically in an ultracold atomic gas.
2000	Yuri Oganessian Physicist	Discovery of Livermorium	Dubna, Russia	Leads collaborative experiments that produce atoms of element 116, later named livermorium, through fusion of heavy nuclei.
2001	Lene Vestergaard Hau Physicist	Stopped Light	Cambridge Massachusetts, Denmark	Stops a light pulse temporarily inside an atomic medium.
2001	Lene Vestergaard Hau Physicist	Stored Optical Information	Cambridge Massachusetts, Denmark	Stores and later retrieves optical information using coherent atomic states.
2013	François Englert	Nobel Prize	Stockholm, Belgium	Shares the Nobel Prize in Physics for the theoretical discovery of the mechanism explaining the origin of mass of subatomic particles.
2013	Peter Higgs	Nobel Prize	Stockholm, Great Britain	Shares the Nobel Prize in Physics for the theoretical discovery of the mechanism explaining the origin of mass of subatomic particles.
2019	Reinhard Dorner Physicist	Electron Correlation Imaging	Frankfurt, Germany	Uses coincidence momentum imaging to study correlated electron motion in atoms and molecules.
2021	Giorgio Parisi	Nobel Prize	Stockholm, Italy	Receives the Nobel Prize in Physics for discovering the interplay of disorder and fluctuations in physical systems from atomic to planetary scales.

Atomic Physics Timeline

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