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Topic: Deriving Beta in Maxwell-Boltzman Velocity Distribution  (Read 2350 times)

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Offline SadBloke

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Deriving Beta in Maxwell-Boltzman Velocity Distribution
« on: January 20, 2014, 04:26:34 AM »
"Perform the following calculation in spherical coordinates. The Maxwell-Boltzman velocity distribution function has the form:

f(u)=(mβ/2Π)3/2e-mβu2/2 where β is a constant. Using the fact that ε = (mu2)/2 = (3/2)kBT = int(dux)int(duy)int(duz)((mu2)/2)f(u) and using also the definition u2=ux2+uy2+uz2 complete the integral and show that β=1/(kBT)

I'll link to my instructor's lecture notes, which I didn't find especially helpful but would give you a sense of what path I'm trying to follow.
http://faculty.washington.edu/gdrobny/Lecture453_1-14_Intro.pdf

I'm currently at page 5, figure 1.14.

I was thinking that the integral in figure 1.14 may be solvable using a generic form but haven't found one that I can fit the equation to.
Any help or insight would be greatly appreciated, as I've been trying to figure it out all weekend and made zero progress.

Offline Corribus

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Re: Deriving Beta in Maxwell-Boltzman Velocity Distribution
« Reply #1 on: January 21, 2014, 12:30:58 PM »
There's an integral here I believe that fits.

http://en.wikipedia.org/wiki/List_of_integrals_of_exponential_functions

(Eighth one under definite integrals).

In the future, please try to use LaTex when writing equations like that. It's easy to misinterpret them the way you have them written.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

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