Rydberg state: Difference between revisions
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{{Short description|Excited quantum states with the convenient Rydberg energy formula}} |
{{Short description|Excited quantum states with the convenient Rydberg energy formula}} |
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The '''Rydberg states'''<ref>https://discovery.princeton.edu/2016/11/15/students-create-exotic-state-of-matter/</ref> of an [[atom]] or [[molecule]] are electronically [[ |
The '''Rydberg states'''<ref>{{Cite web|url=https://discovery.princeton.edu/2016/11/15/students-create-exotic-state-of-matter/|title = Students create exotic state of matter|date = 15 November 2016}}</ref> of an [[atom]] or [[molecule]] are electronically [[excited state]]s with energies that follow the [[Rydberg formula]] as they converge on an ionic state with an [[ionization energy]]. Although the Rydberg formula was developed to describe atomic energy levels, it has been used to describe many other systems that have electronic structure roughly similar to atomic hydrogen.<ref>{{Cite book|title=Rydberg Physics|last1=Šibalić|first1=Nikola|last2=S Adams|first2=Charles|publisher=IOP Publishing|year=2018|isbn=9780750316354|language=en|doi=10.1088/978-0-7503-1635-4|bibcode = 2018ryph.book.....S}}</ref> In general, at sufficiently high [[principal quantum number]]s, an excited electron-ionic core system will have the general character of a [[hydrogen-like atom|hydrogenic system]] and the energy levels will follow the Rydberg formula. Rydberg states have energies converging on the energy of the ion. The ionization energy threshold is the energy required to completely liberate an [[electron]] from the ionic core of an atom or molecule. In practice, a Rydberg [[wave packet]] is created by a laser pulse on a hydrogenic atom and thus populates a superposition of Rydberg states.<ref>{{Cite journal| last1 = Fielding| first = H. H. | title = Rydberg wavepackets in molecules: from observation to control | volume = 56| journal = Annual Review of Physical Chemistry| pages = 91–117 | year = 2005| issn = 0066-426X | pmid = 15796697 | doi = 10.1146/annurev.physchem.55.091602.094428|bibcode = 2005ARPC...56...91F }}</ref> Modern investigations using pump-probe experiments show molecular pathways – e.g. dissociation of [[dinitrogen dioxide|(NO)<sub>2</sub>]] – via these special states.<ref>{{Cite journal| first1 = O.| last2 = Lee | first2 = M.| last4 = Reisler| last3 = Shaffer| last5 = Levchenko | first3 = P. | first4 = H.| last7 = Underwood| last8 = Shi | first5 = V.| last1 = Gessner| last9 = East | first6 = I.| last6 = Krylov | first7 = G. | first8 = H. | first9 = L. | title = Femtosecond multidimensional imaging of a molecular dissociation | first13 = A.| last13 = Stolow | first12 = C. C. | journal = Science| last12 = Hayden | volume = 311 | first11 = E. T. | issue = 5758| last10 = Wardlaw | pages = 219–222| last11 = Chrysostom | date=Jan 2006 | issn = 0036-8075 | doi = 10.1126/science.1120779 | first10 = D. M. | pmid = 16357226|bibcode = 2006Sci...311..219G | s2cid = 40024888 | doi-access = free }}</ref> |
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==Rydberg series== |
==Rydberg series== |
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Rydberg series describe the energy levels associated with partially removing an electron from the ionic core. Each [[Johannes Rydberg|Rydberg]] series converges on an ionization [[energy]] threshold associated with a particular ionic core configuration. These quantized Rydberg energy levels can be associated with the quasiclassical Bohr atomic picture. The closer you get to the ionization threshold energy, the higher the principal quantum number, and the smaller the energy difference between "near threshold Rydberg states." As the electron is promoted to higher energy levels, the spatial excursion of the electron from the ionic core increases and the system is more like the [[Niels Bohr|Bohr]] quasiclassical picture. |
Rydberg series describe the energy levels associated with partially removing an electron from the ionic core. Each [[Johannes Rydberg|Rydberg]] series converges on an ionization [[energy]] threshold associated with a particular ionic core configuration. These quantized Rydberg energy levels can be associated with the quasiclassical Bohr atomic picture. The closer you get to the ionization threshold energy, the higher the principal quantum number, and the smaller the energy difference between "near threshold Rydberg states." As the electron is promoted to higher energy levels, the spatial excursion of the electron from the ionic core increases and the system is more like the [[Niels Bohr|Bohr]] quasiclassical picture. |
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== Rydberg Correction == |
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In atomic physics, '''Rydberg correction''' refers to a subject put into a formula for the energy of a single electron. The energy of [[Rydberg state]]s can be refined by including a correction called the quantum defect in the Rydberg formula. The "[[quantum defect]]" correction is associated with the presence of a distributed ionic core. Even for many electronically excited molecular systems, the ionic core interaction with an excited electron can take on the general aspects of the interaction between the [[proton]] and the electron in the [[hydrogen]] atom. The spectroscopic assignment of these states follows the Rydberg formula and they are called Rydberg states of molecules. The F terms of the formula are extremely small, while the S terms are very large.<ref name="HerzbergSpinks1944">{{cite book|last1=Herzberg|first1=Gerhard|last2=Spinks|first2=John William Tranter|title=Atomic Spectra and Atomic Structure: By Gerhard Herzberg|url=https://books.google.com/books?id=MxdxGPk-LqoC&pg=PA58|accessdate=13 December 2012|year=1944|publisher=Courier Dover Publications|isbn=978-0-486-60115-1|page=58}}</ref> |
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==Energy of Rydberg states== |
==Energy of Rydberg states== |
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==Molecular Rydberg states== |
==Molecular Rydberg states== |
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Although the energy formula of Rydberg series is a result of |
Although the energy formula of Rydberg series is a result of hydrogen-like atom structure, Rydberg states are also present in molecules. [[Wave functions]] of high Rydberg states are very diffuse and span diameters that approach infinity.{{Attribution needed|date=September 2021}}{{Vague|date=September 2021}} As a result, any isolated neutral molecule behaves like a [[hydrogen-like atom]] at the Rydberg limit. For molecules with multiple stable [[Monovalent ion|monovalent]] cations, multiple Rydberg series may exist. Because of the complexity of molecular spectra, low-lying Rydberg states of molecules are often mixed with valence states with similar energy and are thus not pure Rydberg states.<ref>Stohr, J., "NEXAFS Spectroscopy" Springer Series in Surface Science 25, (1992), p. 86.</ref> |
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==See also== |
==See also== |
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==External links== |
==External links== |
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* [https://www.defenseone.com/technology/2021/02/army-creates-quantum-sensor-detects-entire-radio-frequency-spectrum/171939/ Army Creates Quantum Sensor That Detects Entire Radio-Frequency Spectrum]; Defense One. |
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* http://www.phy.davidson.edu/StuHome/joesten/IntLab/final/rydberg.htm |
* [http://www.phy.davidson.edu/StuHome/joesten/IntLab/final/rydberg.htm Rydberg Atoms and the Quantum Defect]; Physics Department, Davidson College. |
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* [http://vergil.chemistry.gatech.edu/notes/excd/node2.html Rydberg Transitions]; Chemistry and Biochemistiry, Georgia Tech. |
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[[Category:Atomic physics]] |
[[Category:Atomic physics]] |
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[[Category:Atomic, molecular, and optical physics]] |
[[Category:Atomic, molecular, and optical physics]] |
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[[de:Rydberg-Zustand]] |
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Latest revision as of 19:08, 21 November 2024
The Rydberg states[1] of an atom or molecule are electronically excited states with energies that follow the Rydberg formula as they converge on an ionic state with an ionization energy. Although the Rydberg formula was developed to describe atomic energy levels, it has been used to describe many other systems that have electronic structure roughly similar to atomic hydrogen.[2] In general, at sufficiently high principal quantum numbers, an excited electron-ionic core system will have the general character of a hydrogenic system and the energy levels will follow the Rydberg formula. Rydberg states have energies converging on the energy of the ion. The ionization energy threshold is the energy required to completely liberate an electron from the ionic core of an atom or molecule. In practice, a Rydberg wave packet is created by a laser pulse on a hydrogenic atom and thus populates a superposition of Rydberg states.[3] Modern investigations using pump-probe experiments show molecular pathways – e.g. dissociation of (NO)2 – via these special states.[4]
Rydberg series
[edit]Rydberg series describe the energy levels associated with partially removing an electron from the ionic core. Each Rydberg series converges on an ionization energy threshold associated with a particular ionic core configuration. These quantized Rydberg energy levels can be associated with the quasiclassical Bohr atomic picture. The closer you get to the ionization threshold energy, the higher the principal quantum number, and the smaller the energy difference between "near threshold Rydberg states." As the electron is promoted to higher energy levels, the spatial excursion of the electron from the ionic core increases and the system is more like the Bohr quasiclassical picture.
Energy of Rydberg states
[edit]The energy of Rydberg states can be refined by including a correction called the quantum defect in the Rydberg formula. The "quantum defect" correction is associated with the presence of a distributed ionic core. Even for many electronically excited molecular systems, the ionic core interaction with an excited electron can take on the general aspects of the interaction between the proton and the electron in the hydrogen atom. The spectroscopic assignment of these states follows the Rydberg formula and they are called Rydberg states of molecules.
Molecular Rydberg states
[edit]Although the energy formula of Rydberg series is a result of hydrogen-like atom structure, Rydberg states are also present in molecules. Wave functions of high Rydberg states are very diffuse and span diameters that approach infinity.[attribution needed][vague] As a result, any isolated neutral molecule behaves like a hydrogen-like atom at the Rydberg limit. For molecules with multiple stable monovalent cations, multiple Rydberg series may exist. Because of the complexity of molecular spectra, low-lying Rydberg states of molecules are often mixed with valence states with similar energy and are thus not pure Rydberg states.[5]
See also
[edit]References
[edit]- ^ "Students create exotic state of matter". 15 November 2016.
- ^ Šibalić, Nikola; S Adams, Charles (2018). Rydberg Physics. IOP Publishing. Bibcode:2018ryph.book.....S. doi:10.1088/978-0-7503-1635-4. ISBN 9780750316354.
- ^ Fielding, H. H. (2005). "Rydberg wavepackets in molecules: from observation to control". Annual Review of Physical Chemistry. 56: 91–117. Bibcode:2005ARPC...56...91F. doi:10.1146/annurev.physchem.55.091602.094428. ISSN 0066-426X. PMID 15796697.
- ^ Gessner, O.; Lee, M.; Shaffer, P.; Reisler, H.; Levchenko, V.; Krylov, I.; Underwood, G.; Shi, H.; East, L.; Wardlaw, D. M.; Chrysostom, E. T.; Hayden, C. C.; Stolow, A. (Jan 2006). "Femtosecond multidimensional imaging of a molecular dissociation". Science. 311 (5758): 219–222. Bibcode:2006Sci...311..219G. doi:10.1126/science.1120779. ISSN 0036-8075. PMID 16357226. S2CID 40024888.
- ^ Stohr, J., "NEXAFS Spectroscopy" Springer Series in Surface Science 25, (1992), p. 86.
- Atomic Spectra and Atomic Structure, Gerhard Herzberg, Prentice-Hall, 1937.
- Atoms and Molecules, Martin Karplus and Richard N. Porter, Benjamin & Company, Inc., 1970.
External links
[edit]- Army Creates Quantum Sensor That Detects Entire Radio-Frequency Spectrum; Defense One.
- Rydberg Atoms and the Quantum Defect; Physics Department, Davidson College.
- Rydberg Transitions; Chemistry and Biochemistiry, Georgia Tech.