Boltzmann constant: Difference between revisions
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Its experimentally determined value (in SI units, 2010 [http://physics.nist.gov/cgi-bin/cuu/Value?k#mid CODATA] value) is: | Its experimentally determined value (in SI units, 2010 [http://physics.nist.gov/cgi-bin/cuu/Value?k#mid CODATA] value) is: | ||
:<math>k_B =1.3806488 \times 10^{-23} | :<math>k_B =1.3806488 \times 10^{-23} \left. JK^{-1}\right.</math> | ||
In units with molecular significance it is close to 1, for example see: [[DL_POLY | DL_POLY units]]. | In units with molecular significance it is close to 1, for example see: [[DL_POLY | DL_POLY units]]. | ||
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Max Planck, [http://nobelprize.org/nobel_prizes/physics/laureates/1918/planck-lecture.html Nobel Lecture, June 2, 1920] | Max Planck, [http://nobelprize.org/nobel_prizes/physics/laureates/1918/planck-lecture.html Nobel Lecture, June 2, 1920] | ||
==Experimental determination of Boltzmann's constant== | ==Experimental determination of Boltzmann's constant== | ||
Boltzmann's constant can be obtained from the ratio of the [[molar gas constant]] to the [[Avogadro constant]]. | Boltzmann's constant can be obtained from the ratio of the [[molar gas constant]] to the [[Avogadro constant]] <ref>[http://dx.doi.org/10.1088/0026-1394/22/3/023 L. Storm "Precision Measurements of the Boltzmann Constant",Metrologia '''22''' pp. 229-234 (1986)]</ref> | ||
<ref>[http://dx.doi.org/10.1088/0957-0233/17/10/R01 B Fellmuth, Ch Gaiser and J Fischer "Determination of the Boltzmann constant—status and prospects", Measurement Science and Technology '''17''' pp. R145-R159 (2006)]</ref>. | |||
The molar gas constant can be obtained via acoustic gas thermometry, and Avogadros constant from either the ''Silicon sphere'', or via the watt balance. | The molar gas constant can be obtained via acoustic gas thermometry, and Avogadros constant from either the ''Silicon sphere'', or via the watt balance. | ||
Recently laser spectroscopy has been used to determine the constant | Recently laser spectroscopy has been used to determine the constant <ref>[http://dx.doi.org/10.1103/PhysRevLett.98.250801 C. Daussy, M. Guinet, A. Amy-Klein, K. Djerroud, Y. Hermier, S. Briaudeau, Ch. J. Bordé, and C. Chardonnet "Direct Determination of the Boltzmann Constant by an Optical Method", Physical Review Letters '''98''' 250801 (2007)]</ref> | ||
<ref>[http://dx.doi.org/10.1103/PhysRevLett.100.200801 G. Casa, A. Castrillo, G. Galzerano, R. Wehr, A. Merlone, D. Di Serafino, P. Laporta, and L. Gianfrani "Primary Gas Thermometry by Means of Laser-Absorption Spectroscopy: Determination of the Boltzmann Constant", Physical Review Letters '''100''' 200801 (2008)]</ref>. Other techniques include Coulomb blockade thermometry <ref>[http://dx.doi.org/10.1103/PhysRevLett.73.2903 J. P. Pekola, K. P. Hirvi, J. P. Kauppinen, and M. A. Paalanen "Thermometry by Arrays of Tunnel Junctions", Physical Review Letters '''73''' pp. 2903-2906 (1994)]</ref> | |||
<ref>[http://dx.doi.org/10.1103/PhysRevLett.101.206801 Jukka P. Pekola, Tommy Holmqvist, and Matthias Meschke "Primary Tunnel Junction Thermometry", Physical Review Letters '''101''' 206801 (2008)]</ref>. | |||
==References== | ==References== | ||
<references/> | |||
[[Category: Physical constants]] | [[Category: Physical constants]] | ||
Latest revision as of 17:01, 23 February 2012
The Boltzmann constant ( or ) is the physical constant relating temperature to energy. It is named after the Austrian physicist Ludwig Eduard Boltzmann. Its experimentally determined value (in SI units, 2010 CODATA value) is:
In units with molecular significance it is close to 1, for example see: DL_POLY units.
History of Boltzmann's constant[edit]
- "This constant is often referred to as Boltzmann's constant, although, to my knowledge, Boltzmann himself never introduced it - a peculiar state of affairs, which can be explained by the fact that Boltzmann, as appears from his occasional utterances, never gave thought to the possibility of carrying out an exact measurement of the constant."
Max Planck, Nobel Lecture, June 2, 1920
Experimental determination of Boltzmann's constant[edit]
Boltzmann's constant can be obtained from the ratio of the molar gas constant to the Avogadro constant [1] [2]. The molar gas constant can be obtained via acoustic gas thermometry, and Avogadros constant from either the Silicon sphere, or via the watt balance. Recently laser spectroscopy has been used to determine the constant [3] [4]. Other techniques include Coulomb blockade thermometry [5] [6].
References[edit]
- ↑ L. Storm "Precision Measurements of the Boltzmann Constant",Metrologia 22 pp. 229-234 (1986)
- ↑ B Fellmuth, Ch Gaiser and J Fischer "Determination of the Boltzmann constant—status and prospects", Measurement Science and Technology 17 pp. R145-R159 (2006)
- ↑ C. Daussy, M. Guinet, A. Amy-Klein, K. Djerroud, Y. Hermier, S. Briaudeau, Ch. J. Bordé, and C. Chardonnet "Direct Determination of the Boltzmann Constant by an Optical Method", Physical Review Letters 98 250801 (2007)
- ↑ G. Casa, A. Castrillo, G. Galzerano, R. Wehr, A. Merlone, D. Di Serafino, P. Laporta, and L. Gianfrani "Primary Gas Thermometry by Means of Laser-Absorption Spectroscopy: Determination of the Boltzmann Constant", Physical Review Letters 100 200801 (2008)
- ↑ J. P. Pekola, K. P. Hirvi, J. P. Kauppinen, and M. A. Paalanen "Thermometry by Arrays of Tunnel Junctions", Physical Review Letters 73 pp. 2903-2906 (1994)
- ↑ Jukka P. Pekola, Tommy Holmqvist, and Matthias Meschke "Primary Tunnel Junction Thermometry", Physical Review Letters 101 206801 (2008)