Lattice parameter + valence + avg time between collisions

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Homework Help Overview

The discussion revolves around calculating the average time between collisions of conduction electrons in a metal with a body-centered cubic (bcc) structure. Participants are examining the relationship between lattice parameters, conductivity, and other physical properties.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of a specific equation for calculating the average time between collisions and raise questions about the values used for variables like electron density and lattice parameters. There is uncertainty regarding the correct lattice parameter value.

Discussion Status

The discussion is ongoing, with participants questioning the accuracy of provided values and clarifying the correct lattice parameter. Some guidance on the equation to use has been offered, but no consensus has been reached regarding the values for the calculations.

Contextual Notes

There is a discrepancy in the reported lattice parameter values, with participants noting different values for the same material in the context of the homework problem versus an example problem.

exzacklyright
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valence Z=1, lattice param a = 4.05 conductivity = 1.76e7 . What's the avg time between collisions of a conduction electron in this metal (bcc structure).really have no idea lol
 
Last edited:
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The equation I think I got to use is : [itex]\tau[/itex]=([itex]\sigma[/itex]*m)/ (n*e^2)

n= 2.52 e28 sigma = 2.38e7 and I'm guessing e = 1.6e-19 but i got the wrong answer.
 
How did you get the value for n? It seems that you have an error there.
 
Since the crystal structure of Na is bcc, there are two Na atoms in each conventional unit cell of volume a^3. Denisty n= 2/a^3... so 2/(4.3e-10)^3=2.52e28
 
In the original post you said that the lattice constant is 4.05A (and not 4.3).
Which one is it?
 
nasu said:
In the original post you said that the lattice constant is 4.05A (and not 4.3).
Which one is it?

ah sorry. in the example problem it's 4.3 but in the homework problem it's 4.05
 

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