[Charkol]

Hello, I have a problem in my book, Quanta Matter and Change, Atkins, that is an assigned question for a problem set.

Please don't do it for me, I just need to know what it is trying to get me to do.

The rotation of a light atom around a heavier atom to which it is bonded can be described quantum mechanically.  The unnormalized wave functions for a light atom confined to move on a circle (with a heavier atom at the circle's centre) are psi(phi) = e^(-im phi), where m = 0, +-1, +-2, +-3... and 0<= phi >=2pi.  Determine phi.

I understand how to normalize wave functions.

And I know the answer... it is pi.  

But what the heck do I do to determine phi?

[Charkol]

Well, I found out what i needed.  For any of those who thought about this question...

what it was asking was for me to find the average value of phi.  that is, as it's written in my book, "< phi >".