Where did the extra 8 come from in the derivation for density of states?

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SUMMARY

The discussion centers on the derivation of the density of states, specifically the discrepancy in the factor of 8 in the equation for g(E). The correct formula is g(E) = (8∏√2/h³)*m^(3/2)*√2, which includes the factor of 8 arising from the relationship between Planck's constant h and the reduced Planck's constant ħ, where ħ = h/(2π). Participants emphasize the importance of correctly applying factors of π in the derivation process.

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Students and researchers in physics, particularly those focusing on quantum mechanics and solid-state physics, will benefit from this discussion as it clarifies the derivation of the density of states and the significance of constants in the equations.

iampaul
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TL;DR
I tried to follow the derivation, but I got a different result
I was looking for a derivation for the density of states and I came across this page: https://ecee.colorado.edu/~bart/book/book/chapter2/ch2_4.htm

I followed the derivation and came up with:
g(E) = (1/L3)dN/dE
= (1/L3)L3/2*k2 * dk/dE
=K2/2 * dk/dE
=K2/2 *
g(E) = (∏√2/h3)*m3/2*√2but the book gives:
g(E) = (8∏√2/h3)*m3/2*√2

where did the extra 8 come from?
 
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Check your math. You miss some factors ##\pi##.
The 8 comes from the ##\ \hbar^3\ ## and ##\ \hbar = {h\over2\pi}##
 
BvU said:
Check your math. You miss some factors ##\pi##.
The 8 comes from the ##\ \hbar^3\ ## and ##\ \hbar = {h\over2\pi}##
Thanks, I've been plugging in ##\ \hbar = {h\over\pi}##.
 

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