Atomic, molecular, and optical physics
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Quantum mechanics |
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Atomic, molecular, and optical physics (AMO) is the study of
Atomic and molecular physics
Atomic physics is the subfield of AMO that studies atoms as an isolated system of
Both subfields are primarily concerned with
As with many scientific fields, strict delineation can be highly contrived and atomic physics is often considered in the wider context of atomic, molecular, and optical physics. Physics research groups are usually so classified.
Optical physics
Optical physics is the study of the generation of
Researchers in optical physics use and develop light sources that span the
Other important areas of research include the development of novel optical techniques for nano-optical measurements,
History
One of the earliest steps towards atomic physics was the recognition that matter was composed of atoms, in modern terms the basic unit of a
Later, the connection between atomic physics and optical physics became apparent, by the discovery of
From that time to the 1920s, physicists were seeking to explain
Experiments including
Classical oscillator model of matter
Early models to explain the origin of the
Early quantum model of matter and light
Max Planck derived a formula to describe the electromagnetic field inside a box when in thermal equilibrium in 1900.[16]: 8–9 His model consisted of a superposition of
can occur in the box, where n is a positive integer (mathematically denoted by ). The equation describing these standing waves is given by:
- .
where E0 is the magnitude of the electric field amplitude, and E is the magnitude of the electric field at position x. From this basic, Planck's law was derived.[16]: 4–8, 51–52
In 1911, Ernest Rutherford concluded, based on alpha particle scattering, that an atom has a central pointlike proton. He also thought that an electron would be still attracted to the proton by Coulomb's law, which he had verified still held at small scales. As a result, he believed that electrons revolved around the proton. Niels Bohr, in 1913, combined the Rutherford model of the atom with the quantisation ideas of Planck. Only specific and well-defined orbits of the electron could exist, which also do not radiate light. In jumping orbit the electron would emit or absorb light corresponding to the difference in energy of the orbits. His prediction of the energy levels was then consistent with observation.[16]: 9–10
These results, based on a discrete set of specific standing waves, were inconsistent with the continuous classical oscillator model.[16]: 8
Work by Albert Einstein in 1905 on the photoelectric effect led to the association of a light wave of frequency with a photon of energy . In 1917 Einstein created an extension to Bohrs model by the introduction of the three processes of stimulated emission, spontaneous emission and absorption (electromagnetic radiation).[16]: 11
Modern treatments
The largest steps towards the modern treatment was the formulation of quantum mechanics with the matrix mechanics approach by Werner Heisenberg and the discovery of the Schrödinger equation by Erwin Schrödinger.[16]: 12
There are a variety of semi-classical treatments within AMO. Which aspects of the problem are treated quantum mechanically and which are treated classically is dependent on the specific problem at hand. The semi-classical approach is ubiquitous in computational work within AMO, largely due to the large decrease in computational cost and complexity associated with it.
For matter under the action of a laser, a fully quantum mechanical treatment of the atomic or molecular system is combined with the system being under the action of a classical electromagnetic field.[16]: 14 Since the field is treated classically it can not deal with spontaneous emission.[16]: 16 This semi-classical treatment is valid for most systems,[2]: 997 particular those under the action of high intensity laser fields.[2]: 724 The distinction between optical physics and quantum optics is the use of semi-classical and fully quantum treatments respectively.[2]: 997
Within collision dynamics and using the semi-classical treatment, the internal degrees of freedom may be treated quantum mechanically, whilst the relative motion of the quantum systems under consideration are treated classically.[2]: 556 When considering medium to high speed collisions, the nuclei can be treated classically while the electron is treated quantum mechanically. In low speed collisions the approximation fails.[2]: 754
Classical Monte-Carlo methods for the dynamics of electrons can be described as semi-classical in that the initial conditions are calculated using a fully quantum treatment, but all further treatment is classical.[2]: 871
Isolated atoms and molecules
Atomic, Molecular and Optical physics frequently considers atoms and molecules in isolation. Atomic models will consist of a single nucleus that may be surrounded by one or more bound electrons, whilst molecular models are typically concerned with molecular hydrogen and its
While modelling atoms in isolation may not seem realistic, if one considers molecules in a gas or plasma then the time-scales for molecule-molecule interactions are huge in comparison to the atomic and molecular processes that we are concerned with. This means that the individual molecules can be treated as if each were in isolation for the vast majority of the time. By this consideration atomic and molecular physics provides the underlying theory in plasma physics and atmospheric physics even though both deal with huge numbers of molecules.
Electronic configuration
Electrons form notional shells around the nucleus. These are naturally in a ground state but can be excited by the absorption of energy from light (photons), magnetic fields, or interaction with a colliding particle (typically other electrons).
Electrons that populate a shell are said to be in a bound state. The energy necessary to remove an electron from its shell (taking it to infinity) is called the binding energy. Any quantity of energy absorbed by the electron in excess of this amount is converted to kinetic energy according to the conservation of energy. The atom is said to have undergone the process of ionization.
In the event that the electron absorbs a quantity of energy less than the binding energy, it may transition to an
There are strict
See also
- Born–Oppenheimer approximation
- Frequency doubling
- Diffraction
- Hyperfine structure
- Interferometry
- Isomeric shift
- Metamaterial cloaking
- Molecular energy state
- Molecular modeling
- Nanotechnology
- Negative index metamaterials
- Nonlinear optics
- Optical engineering
- Photon polarization
- Quantum chemistry
- Quantum optics
- Rigid rotor
- Spectroscopy
- Superlens
- Stationary state
- Transition of state
Notes
- ^ ISBN 978-0-309-03575-0.
- ^ ISBN 978-0-387-20802-2.
- ISBN 978-1-60456-907-0.
- ISBN 978-0-07-051400-3.
- ISBN 978-0-19-855148-5.
- ISBN 978-0-19-856646-5.
- ISBN 978-0-471-89931-0.
- ^ "Optical Physics". University of Arizona. Archived from the original on May 13, 2019. Retrieved Apr 23, 2014.
- ^ "Slow Light". Science Watch. Retrieved Jan 22, 2013.
- ISBN 978-0-471-89931-0.
- ISBN 978-0-07-051400-3.
- ISBN 978-0-19-856646-5.
- ^ ISBN 978-0-19-855148-5.
- ISBN 978-0-471-89931-0.
- ISBN 978-0-7167-8964-2.
- ^ ISBN 978-0-444-86020-0.
References
- Bransden, B. H.; Joachain, CJ (2002). Physics of Atoms and Molecules (2nd ed.). Prentice Hall. ISBN 978-0-582-35692-4.
- Foot, C. J. (2004). Atomic Physics. Oxford University Press. ISBN 978-0-19-850696-6.
- Herzberg, G. (1979) [1945]. Atomic Spectra and Atomic Structure. Dover. ISBN 978-0-486-60115-1.
- Condon, E. U. & Shortley, G. H. (1935). The Theory of Atomic Spectra. Cambridge University Press. ISBN 978-0-521-09209-8.
- Cowan, Robert D. (1981). The Theory of Atomic Structure and Spectra. University of California Press. ISBN 978-0-520-03821-9.
- Lindgren, I. & Morrison, J. (1986). Atomic Many-Body Theory (Second ed.). Springer-Verlag. ISBN 978-0-387-16649-0.
- J. R. Hook; H. E. Hall (2010). Solid State Physics (2nd ed.). Manchester Physics Series, John Wiley & Sons. ISBN 978-0-471-92804-1.
- P. W. Atkins (1978). Physical chemistry. Oxford University Press. ISBN 978-0-19-855148-5.
- Y. B. Band (2010). Light and Matter: Electromagnetism, Optics, Spectroscopy and Lasers. John Wiley & Sons. ISBN 978-0-471-89931-0.
- I. R. Kenyon (2008). The Light Fantastic – Introduction to Classic and Quantum Optics. Oxford University Press. ISBN 978-0-19-856646-5.
- T.Hey, P.Walters (2009). The New Quantum Universe. Cambridge University Press. ISBN 978-0-521-56457-1.
- R. Loudon (1996). The Quantum Theory of Light. Oxford University Press (Oxford Science Publications). ISBN 978-0-19-850177-0.
- R. Eisberg; R. Resnick (1985). Quantum Physics of Atoms, Molecules, Solids, Nuclei, and Particles (2nd ed.). John Wiley & Sons. ISBN 978-0-471-87373-0.
- P.W. Atkins (1974). Quanta: A handbook of concepts. Oxford University Press. ISBN 978-0-19-855493-6.
- E. Abers (2004). Quantum Mechanics. Pearson Ed., Addison Wesley, Prentice Hall Inc. ISBN 978-0-13-146100-0.
- P.W. Atkins (1977). Molecular Quantum Mechanics Parts I and II: An Introduction to QUANTUM CHEMISTRY (Volume 1). Oxford University Press. ISBN 978-0-19-855129-4.
- P.W. Atkins (1977). Molecular Quantum Mechanics Part III: An Introduction to QUANTUM CHEMISTRY (Volume 2). Oxford University Press. ISBN 978-0-19-855129-4.
- Solid State Physics (2nd Edition), J.R. Hook, H.E. Hall, Manchester Physics Series, John Wiley & Sons, 2010, ISBN 978 0 471 92804 1
- Light and Matter: Electromagnetism, Optics, Spectroscopy and Lasers, Y.B. Band, John Wiley & Sons, 2010, ISBN 978-0471-89931-0
- The Light Fantastic – Introduction to Classic and Quantum Optics, I.R. Kenyon, Oxford University Press, 2008, ISBN 978-0-19-856646-5
- Handbook of atomic, molecular, and optical physics, Editor: Gordon Drake, ISBN 0-387-20802-X
- Fox, Mark (2010). Optical properties of solids. Oxford New York: Oxford University Press. ISBN 978-0-19-957336-3.
External links
- ScienceDirect - Advances In Atomic, Molecular, and Optical Physics
- Journal of Physics B: Atomic, Molecular and Optical Physics
Institutions
- American Physical Society - Division of Atomic, Molecular & Optical Physics
- European Physical Society - Atomic, Molecular & Optical Physics Division
- National Science Foundation - Atomic, Molecular and Optical Physics
- MIT-Harvard Center for Ultracold Atoms
- Stanford QFARM Initiative for Quantum Science & Enginneering
- JILA - Atomic and Molecular Physics
- Joint Quantum Institute at University of Maryland and NIST
- ORNL Physics Division
- Queen's University Belfast - Center for Theoretical, Atomic, Molecular and Optical Physics,
- University of California, Berkeley - Atomic, Molecular and Optical Physics