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Dilithium

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This article is about the real substance. For other uses, seeDilithium (disambiguation).
Dilithium
Wireframe model of dilithium
Spacefill model of dilithium
Names
IUPAC name
Dilithium(Li—Li)[citation needed]
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/2LicheckY
    Key: SMBQBQBNOXIFSF-UHFFFAOYSA-NcheckY
  • [Li][Li]
Properties
Li2
Molar mass 13.88g·mol−1
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).

Dilithium,Li2,is a stronglyelectrophilic,diatomicmolecule comprising twolithiumatomscovalently bondedtogether. Li2has been observed in thegasphase. It has abond orderof 1, an internuclear separation of 267.3pmand abond energyof 102 kJ/mol or 1.06 eV in each bond.[1] Theelectron configurationof Li2may be written as σ2.[citation needed]

Being the third-lightest stable[citation needed]neutralhomonucleardiatomic molecule(afterdihydrogenanddihelium), dilithium is an extremely important model system for studying fundamentals of physics, chemistry, andelectronic structure theory.

It is the most thoroughly characterized compound in terms of the accuracy and completeness of the empiricalpotential energy curvesof its electronic states. Analytic empirical potential energy curves have been constructed for the X-state,[2]a-state,[3]A-state,[4]c-state,[5]B-state,[6]2d-state,[7]l-state,[7]E-state,[8]and the F-state.[clarification needed][9]The most reliable of these potential energy curves are of theMorse/Long-rangevariety (see entries in the table below).[2][3][6][4][5]

Li2potentials are often used to extract atomic properties. For example, the C3value for atomic lithium extracted from the A-state potential of Li2by Le Roy et al. in[2]is more precise than any previously measured atomic oscillator strength.[10] This lithium oscillator strength is related to the radiative lifetime of atomic lithium and is used as a benchmark for atomic clocks and measurements of fundamental constants.

Electronic state Spectroscopic symbol[clarification needed] Term symbol Bond length(pm) Dissociation energy (cm−1) Bound vibrational levels References
1 (Ground) X 11Σg+ 267
 .298 74(19)[2] 8 516
 .780 0(23)[2] 39[2] [2]
2 a 13Σu+ 417
 .000 6(32)[3] 333
 .779 5(62)[3] 11[3] [3]
3 b 13Πu [7]
4 A 11Σg+ 310
 .792 88(36)[2] 9 353
 .179 5 (28)[2] 118[2] [2]
5 c 13Σg+ 306
 .543 6(16)[3] 7 093
 .492 6(86)[3] 104[3]
6 B 11Πu 293
 .617 142(310)[6] 2 984
 .444[6] 118[6]
7 E 3(?)1Σg+ [8]

See also

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References

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  1. ^Chemical Bonding,Mark J. Winter, Oxford University Press,1994,ISBN0-19-855694-2
  2. ^abcdefghijkLe Roy, Robert J.; N. S. Dattani; J. A. Coxon; A. J. Ross; Patrick Crozet; C. Linton (25 November 2009). "Accurate analytic potentials for Li2(X) and Li2(A) from 2 to 90 Angstroms, and the radiative lifetime of Li(2p) ".Journal of Chemical Physics.131(20): 204309.Bibcode:2009JChPh.131t4309L.doi:10.1063/1.3264688.PMID19947682.
  3. ^abcdefghiDattani, N. S.; R. J. Le Roy (8 May 2013). "A DPF data analysis yields accurate analytic potentials for Li2(a)and Li2(c) that incorporate 3-state mi xing near the c-state asymptote ".Journal of Molecular Spectroscopy.268(1–2): 199–210.arXiv:1101.1361.Bibcode:2011JMoSp.268..199..doi:10.1016/j.jms.2011.03.030.S2CID119266866.
  4. ^abW. Gunton, M. Semczuk, N. S. Dattani, K. W. Madison,High resolution photoassociation spectroscopy of the6Li2A-state,https://arxiv.org/abs/1309.5870
  5. ^abSemczuk, M.; Li, X.; Gunton, W.; Haw, M.; Dattani, N. S.; Witz, J.; Mills, A. K.; Jones, D. J.; Madison, K. W. (2013). "High-resolution photoassociation spectroscopy of the6Li2c-state ".Phys. Rev. A.87(5): 052505.arXiv:1309.6662.Bibcode:2013PhRvA..87e2505S.doi:10.1103/PhysRevA.87.052505.S2CID119263860.
  6. ^abcdeHuang, Yiye; R. J. Le Roy (8 October 2003). "Potential energy Lambda double and Born-Oppenheimer breakdown functions for the B1Piu"barrier" state of Li2".Journal of Chemical Physics.119(14): 7398–7416.Bibcode:2003JChPh.119.7398H.doi:10.1063/1.1607313.
  7. ^abcLi, Dan; F. Xie; L. Li; A. Lazoudis; A. M. Lyyra (29 September 2007). "New observation of the, 13Δg, and 23Πg states and molecular constants with all6Li2,7Li2,and6Li7Li data ".Journal of Molecular Spectroscopy.246(2): 180–186.Bibcode:2007JMoSp.246..180L.doi:10.1016/j.jms.2007.09.008.
  8. ^abJastrzebski, W; A. Pashov; P. Kowalczyk (22 June 2001). "The E-state of lithium dimer revised".Journal of Chemical Physics.114(24): 10725–10727.Bibcode:2001JChPh.11410725J.doi:10.1063/1.1374927.
  9. ^Pashov, A; W. Jastzebski; P. Kowalczyk (22 October 2000). "The Li2F "shelf" state: Accurate potential energy curve based on the inverted perturbation approach ".Journal of Chemical Physics.113(16): 6624–6628.Bibcode:2000JChPh.113.6624P.doi:10.1063/1.1311297.
  10. ^Tang, Li-Yan; Yan, Zong-Chao; Shi, Ting-Yun; Mitroy, J. (2011)."Third-order perturbation theory for van der Waals interaction coefficients"(PDF).Physical Review A.84(5): 052502.Bibcode:2011PhRvA..84e2502T.doi:10.1103/PhysRevA.84.052502.ISSN1050-2947.S2CID122544942.Archived fromthe original(PDF)on 2020-06-25.

Further reading

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