Dipole moment: Difference between revisions
(New page: The '''electric dipole moment''' is a measure of polarity. It is the second term in a multipole expansion of a field (the first one being the monopole, or Coulombic, term.) Its definition,...) |
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The '''electric dipole moment''' is a measure of polarity. It is the second term in a multipole expansion of a field (the first one being the monopole, or Coulombic, term.) Its definition, for a system of point charges, is | The '''electric dipole moment''' is a measure of polarity. It is the second term in a multipole expansion of a field (the first one being the monopole, or Coulombic, term.) Its definition, for a system of point charges, is | ||
<math>\mathbf{p} = \sum_{i=1}^N \, q_i \, \mathbf{r}_i.</math> | <math>\mathbf{p} = \sum_{i=1}^N \, q_i \, \mathbf{r}_i.</math> | ||
For molecular systems, it is customarily given in units of Debyes, after the physicist [[Peter J. W. Debye]]. | For molecular systems, it is customarily given in units of Debyes, after the physicist [[Peter J. W. Debye]]. | ||
In SI units, <math>1</math>D equals approximately <math>3.33564\times 10^{-30}</math> Coulomb-meter (exactly <math>10^{-21}</math>C m<math>^2</math>/s divided by <math>c</math>, the speed of light in vacuum). Conversely, 1 C m = <math>2.9979 10^{29}</math>D. | In SI units, <math>1</math>D equals approximately <math>3.33564\times 10^{-30}</math> Coulomb-meter (exactly <math>10^{-21}</math>C m<math>^2</math>/s divided by <math>c</math>, the speed of light in vacuum). Conversely, 1 C m = <math>2.9979 10^{29}</math>D. | ||
Revision as of 14:24, 23 May 2008
The electric dipole moment is a measure of polarity. It is the second term in a multipole expansion of a field (the first one being the monopole, or Coulombic, term.) Its definition, for a system of point charges, is
For molecular systems, it is customarily given in units of Debyes, after the physicist Peter J. W. Debye. In SI units, Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 1} D equals approximately Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 3.33564\times 10^{-30}} Coulomb-meter (exactly Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 10^{-21}} C mFailed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle ^2} /s divided by Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle c} , the speed of light in vacuum). Conversely, 1 C m = Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 2.9979 10^{29}} D.