Maxwell speed distribution
The probability that the speed of a molecule of mass m lies in the range v to v+dv is given 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 P(v)dv = 4 \pi v^2 dv \left( \frac{m}{2 \pi k_B T} \right)^{3/2} \exp (-mv^2/2k_B T) }
where T is the temperature and 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 k_B} is the Boltzmann constant. The maximum of this distribution is located at
- 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 v_{\rm max} = \sqrt{\frac{2k_BT}{m}}}
The mean speed is given by
- Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\overline {v}}={\frac {2}{\sqrt {\pi }}}v_{\rm {max}}}
and the root-mean-square speed 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 \sqrt{\overline{v^2}} = \sqrt \frac{3}{2} v_{\rm max}}
Derivation
References
- J. C. Maxwell "", British Association for the Advancement of Science 29 Notices and Abstracts 9 (1859)
- J. C. Maxwell "", Philosophical Magazine 19 pp. 19 (1860)
- J. C. Maxwell "", Philosophical Magazine 20 pp. 21 (1860)
- J. Clerk Maxwell "On the Dynamical Theory of Gases", Philosophical Transactions of the Royal Society of London 157 pp. 49-88 (1867)
- J. S. Rowlinson "The Maxwell-Boltzmann distribution", Molecular Physics 103 pp. 2821 - 2828 (2005)