Debye's Assumptions For Heat Capacity

[yasef]

What are the Debye model`s assumptions for heat capacity or density of states? According to the einstein model we assume that N oscillators of the same frequency [ω][/o] and in one dimention. In three dimention N is replaced by 3N, there being three modes per oscillator.

[ardie]

the Deybe model assumes the same as Einstein's except that the frequency of oscillations is not a single w but a distribution from phase space.

[DrDu]

Debye expounded the assumptions in quite some detail:
http://onlinelibrary.wiley.com/doi/10.1002/andp.19123441404/abstract

[yasef]

Thanks for help.

[asifadio]

hello, i would like to as about the derivation of einstein model of specific heat.. this is the derivation that i copied from a book
http://i38.photobucket.com/albums/e122/asifadio/EP8.jpg

how the average energy equation(the summation on both numerator and denominator) can be solve to be like the one in the below of the picture?(below the statement 'solve to get')

[ardie]

using a geometric progression