# Average energy of a harmonic oscillator

1. Sep 7, 2009

### Rajini

Hello PF members,
Is there some good book, which contain the derivation of average energy of a harmonic oscillator at temperature T. I want to derive from Planck's distribution (PD) function (<n>=(exp($$\hbar\omega/kT$$)-1)$$^{-1}$$)....to get the following relation:
energy E= ($$\hbar\omega$$/2)+($$\hbar\omega$$/PD). I referred to some books/www..they mainly refer E= $$\hbar\omega$$(n+(1/2))...stating n as 0,1,2,3,etc...
But i think this n is simply the PD..
Can some one help me..
thanks