Chemicals/Lithiums

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This spectrograph shows the visual spectral lines of lithium. Credit: T c951.

Lithiums is a lecture from the school of chemistry about the various lithiums that occur or are manufactured.

Violets

"Violet satellite bands are caused by those lithium atoms which undergo an optical transition while a helium atom is nearby."[1]

Glasses

"In the other series of glasses, Li, Na, and K, in particular, that can be formed out to x=0.75, the IR spectra clearly show that this structural group becomes the dominant group in the glass at this composition [4], [5] and [43]."[2]

Glaciers

"Taylor Valley glaciers have the lowest lithium concentrations and lightest δ7Li values in the McMurdo Dry Valleys aquatic system."[3]

"The δ7Li ratios of the glacial snow are among the lightest values observed in surface and groundwater samples (+0.8 to +2.9‰) and are unlike seawater (+30.8‰) (Tomascak, 2004; Rosner et al., 2007). This suggests that marine aerosol or marine-derived salts are not the primary sources of lithium to the glacier surfaces [...] Generally, geologic materials are isotopically lighter than natural water samples because of the preferential retention of 6Li in the solid phase. Despite this general relationship, Taylor Valley glacier snow samples have δ7Li signatures more like granite and rhyolite, which range from −1.2 to +8.0‰ (Tomascak, 2004). Although this wide range of Li isotopic values for granite does not conclusively mean the source to the glaciers is felsic rock, the snow samples are extremely light and resemble aluminosilicates. We therefore conclude that the major source of Li in the glacier ice is likely the dissolution of silicate materials."[3]

Sun

"[T]he standard solar models have enjoyed tremendous success recently in terms of agreement between the predicted outer structure and the results from helioseismology[, but] some observed properties of the Sun still defy explanation, such as the degree of Li depletion" [the "solar Li abundance is roughly a factor of 200 below the meteoritic abundance"].[4]

Red giants

In some 824 red giant stars, the Li I 670.78 nm line was detected in several stars, "but only the five objects ... presented a strong line."[5]

"The lithium content of red-giant stars is highly variable (Wallerstein and Conti 1969). The largest amounts of lithium are found in three carbon stars, WZ Cas, WX Cyg, and T Ara, being of the order of 10-2 of calcium. ... Boesgaard (1970) has found a similar high lithium abundance in the S star T Sgr. This is a higher ratio of lithium to calcium than is found in T Tauri stars or in meteorites."[6]

Brown dwarfs

Some of the incontrovertible brown dwarf substellar objects are "identified by the presence of the 670.8 nm lithium [I] line. The most notable of these objects was Gliese 229B, which was found to have a temperature and luminosity well below the stellar range. Remarkably, its near-infrared spectrum clearly exhibited a methane absorption band at 2 micrometres, a feature that had previously only been observed in gas giant atmospheres and the atmosphere of Saturn's moon, Titan. Methane absorption is not expected at the temperatures of main-sequence stars. This discovery helped to establish yet another spectral class even cooler than L dwarfs known as "T dwarfs" for which Gl 229B is the prototype. ... Lithium is generally present in brown dwarfs and not in low-mass stars. [T]he presence of the lithium line in a candidate brown dwarf's spectrum is a strong indicator that it is indeed substellar. The use of lithium to distinguish candidate brown dwarfs from low-mass stars is commonly referred to as the lithium test ... Some brown dwarfs emit X-rays; and all "warm" dwarfs continue to glow tellingly in the red and infrared spectra until they cool to planetlike temperatures (under 1000 K)."[7]

Research

Hypothesis:

  1. Lithium can be produced by muon induced fusion.

Control groups

This is an image of a Lewis rat. Credit: Charles River Laboratories.

The findings demonstrate a statistically systematic change from the status quo or the control group.

“In the design of experiments, treatments [or special properties or characteristics] are applied to [or observed in] experimental units in the treatment group(s).[8] In comparative experiments, members of the complementary group, the control group, receive either no treatment or a standard treatment.[9]"[10]

Proof of concept

Def. a “short and/or incomplete realization of a certain method or idea to demonstrate its feasibility"[11] is called a proof of concept.

Def. evidence that demonstrates that a concept is possible is called proof of concept.

The proof-of-concept structure consists of

  1. background,
  2. procedures,
  3. findings, and
  4. interpretation.[12]

See also

References

  1. ↑ G. D. Mahan (April 24, 1972). "Violet satellite bands in the spectra of Li perturbed by He". Physics Letters A 39 (2): 145-6. doi:10.1016/0375-9601(72)91056-0. http://www.sciencedirect.com/science/article/pii/0375960172910560. Retrieved 2013-03-23.
  2. ↑ Jaephil Cho, Steve W Martin (March 2002). "Infrared spectroscopy of glasses and polycrystals in the series xCs2S+(1−x)B2S3". Journal of non-crystalline solids 298 (2-3): 176-92. http://www.sciencedirect.com/science/article/pii/S0022309302009171. Retrieved 2013-08-28.
  3. 1 2 RA Witherow, WB Lyons, GM Henderson (2010). "Lithium isotopic composition of the McMurdo Dry Valleys aquatic systems". Chemical Geology 275: 139-47. doi:10.1016/j.chemgeo.2010.04.017. ftp://ftp.seti.org/jbishop/AntarcticDryValleys/papers/Witherow(2010)ChemGeol_Li_isotopes_DryValleys.pdf. Retrieved 2014-09-20.
  4. ↑ Jeremy R. King, Constantine P. Deliyannis, and Merchant Boesgaard (April 1, 1997). "The 9Be Abundances of α Centauri A and B and the Sun: Implications for Stellar Evolution and Mixing". The Astrophysical Journal 478 (2): 778. http://iopscience.iop.org/0004-637X/478/2/778/pdf/0004-637X_478_2_778.pdf. Retrieved 2012-07-11.
  5. ↑ L. Monaco, S. Villanova, C. Moni Bidin, G. Carraro, D. Geisler, P. Bonifacio, O. A. Gonzalez, M. Zoccali and L. Jilkova (May 2011). "Lithium-rich giants in the Galactic thick disk". Astronomy & Astrophysics 529 (5): 10. doi:10.1051/0004-6361/201016285.
  6. ↑ A. G. W. Cameron and W. A. Fowler (February 1971). "Lithium and the s-PROCESS in Red-Giant Stars". The Astrophysical Journal 164 (02): 111-4. doi:10.1086/150821. http://adsabs.harvard.edu/abs/1971ApJ...164..111C. Retrieved 2013-08-01.
  7. ↑ "Brown dwarf, In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. June 16, 2012. Retrieved 2012-07-11.
  8. ↑ Klaus Hinkelmann, Oscar Kempthorne (2008). Design and Analysis of Experiments, Volume I: Introduction to Experimental Design (2nd ed.). Wiley. ISBN 978-0-471-72756-9. http://books.google.com/?id=T3wWj2kVYZgC&printsec=frontcover.
  9. ↑ R. A. Bailey (2008). Design of comparative experiments. Cambridge University Press. ISBN 978-0-521-68357-9. http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=9780521683579.
  10. ↑ "Treatment and control groups, In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. May 18, 2012. Retrieved 2012-05-31.
  11. ↑ "proof of concept, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. November 10, 2012. Retrieved 2013-01-13.
  12. ↑ Ginger Lehrman and Ian B Hogue, Sarah Palmer, Cheryl Jennings, Celsa A Spina, Ann Wiegand, Alan L Landay, Robert W Coombs, Douglas D Richman, John W Mellors, John M Coffin, Ronald J Bosch, David M Margolis (August 13, 2005). "Depletion of latent HIV-1 infection in vivo: a proof-of-concept study". Lancet 366 (9485): 549-55. doi:10.1016/S0140-6736(05)67098-5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1894952/. Retrieved 2012-05-09.

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