Difference between revisions of "Hartree"
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The '''hartree''' (symbol: '''''E''<sub>h</sub>'''), also known as the '''Hartree energy''', is the [[atomic unit]] of [[energy]], named after the [[United Kingdom|British]] [[physicist]] [[Douglas Hartree]]. It is defined as the [[electric potential energy]] of the [[hydrogen]] [[atom]] in its [[ground state]], and is equal to 2''R''<sub>∞</sub>''hc''<sub>0</sub>, where ''R''<sub>∞</sub> is the [[Rydberg constant]], ''h'' is the [[Planck constant]] and ''c''<sub>0</sub> is the [[speed of light]]. The 2006 [[CODATA recommended value]] is ''E''<sub>h</sub> = {{nowrap|4.359 743 94(22){{e|−18}} J}} = {{nowrap|27.211 383 86(68) eV}}.<ref>{{CODATA 2006|url=http://physics.nist.gov/cgi-bin/cuu/Value?hr}}.</ref> | The '''hartree''' (symbol: '''''E''<sub>h</sub>'''), also known as the '''Hartree energy''', is the [[atomic unit]] of [[energy]], named after the [[United Kingdom|British]] [[physicist]] [[Douglas Hartree]]. It is defined as the [[electric potential energy]] of the [[hydrogen]] [[atom]] in its [[ground state]], and is equal to 2''R''<sub>∞</sub>''hc''<sub>0</sub>, where ''R''<sub>∞</sub> is the [[Rydberg constant]], ''h'' is the [[Planck constant]] and ''c''<sub>0</sub> is the [[speed of light]]. The 2006 [[CODATA recommended value]] is ''E''<sub>h</sub> = {{nowrap|4.359 743 94(22){{e|−18}} J}} = {{nowrap|27.211 383 86(68) eV}}.<ref>{{CODATA 2006|url=http://physics.nist.gov/cgi-bin/cuu/Value?hr}}.</ref> | ||
| − | The hartree energy is approximately twice the [[ionization energy]] of hydrogen: the relationship is | + | The hartree energy is approximately twice the [[ionization energy]] of hydrogen: the relationship is not exact because the nucleus of the hydrogen atom does not have infinite [[mass]]. However, the relationship ''E''<sub>h</sub> = 2''R''<sub>∞</sub>''hc''<sub>0</sub> is exact, as the effects of non-infinite nuclear mass are already considered in the Rydberg constant (hence the subscript infinity). |
The hartree is usually used as a unit of energy in [[calculational chemistry]]: for experimental measurements at the atomic scale, the [[electronvolt]] (eV) or the [[reciprocal centimetre]] (cm<sup>−1</sup>) are much more widely used. | The hartree is usually used as a unit of energy in [[calculational chemistry]]: for experimental measurements at the atomic scale, the [[electronvolt]] (eV) or the [[reciprocal centimetre]] (cm<sup>−1</sup>) are much more widely used. | ||
Revision as of 06:28, 28 March 2010
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The hartree (symbol: Eh), also known as the Hartree energy, is the atomic unit of energy, named after the British physicist Douglas Hartree. It is defined as the electric potential energy of the hydrogen atom in its ground state, and is equal to 2R∞hc0, where R∞ is the Rydberg constant, h is the Planck constant and c0 is the speed of light. The 2006 CODATA recommended value is Eh = 4.359 743 94(22) × 10−18 J = 27.211 383 86(68) eV.[1]
The hartree energy is approximately twice the ionization energy of hydrogen: the relationship is not exact because the nucleus of the hydrogen atom does not have infinite mass. However, the relationship Eh = 2R∞hc0 is exact, as the effects of non-infinite nuclear mass are already considered in the Rydberg constant (hence the subscript infinity).
The hartree is usually used as a unit of energy in calculational chemistry: for experimental measurements at the atomic scale, the electronvolt (eV) or the reciprocal centimetre (cm−1) are much more widely used.
References
- ↑ Mohr, Peter J.; Taylor, Barry N.; Newell, David B. CODATA Recommended Values of the Fundamental Physical Constants: 2006. Rev. Mod. Phys. 2008, 80 (2), 633–730. doi:10.1103/RevModPhys.80.633, <http://physics.nist.gov/cuu/Constants/codata.pdf>. Direct link to value.
External links
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See also the corresponding article on Wikipedia. |
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