Monday, October 16, 2017

homework and exercises - Maxwell-Boltzmann distribution for transport equations


I have to calculate the transport coefficients for the Maxwell-Boltzmann distribution. But I'm not sure what distribution I have to use. As far as I know it should not be the MB distribution for v-space (Velocity) or E-axis (Energy), since that will get me the wrong dimensions in the end. I have to use the distribution per state.


But I'm not sure how this looks. The integral I have to solve, for me getting the electrical conductivity (1st transport coefficient) I need, is given by:


L(0)=(2m2)3/2e2τπ2m(fMBε)ε3/2dε,


at least, again, when trying to calculate the electrical conductivity, which in the end should end up being Drudes formula σ=ne2τm.


So basically, not hard. But I have to get the distribution function right.


As far as I know the MB-distribution is given by:


fMB(ε)=Ceε/kBT,


where C is what I need to figure out, since that will determine the dimensions of my coefficients.


According to my book the normalized MB distribution function is:



ˉn=ˉNZ1(T,V)eε/kBT,


where:


Z1(T,V)ˉN=VˉN(2πmkBTh2)Zint(T),


and Zint(T)=1 in my case.


But I'm not quite sure how to about this? As far as I can see, it's not just inserting the reversed term of this in C - at least not from what I can see. Maybe it's the V/N I'm not sure about.


Well, anyone who can give me a clue?




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