Temperature for "melting" vibrational degrees of freedom

[RingNebula57]

Hello everyone!
I recently read some information about the equipartition theorem and degrees of freedom in thermodinamics. I read that for the linear N-atomic and non-linear N-atomic molecules in order to allow the vibrational degrees of freedom to appear we need a really high temperature.
I was curious , because I didn't find the value, at about what temperature do those degrees of freedom appear , what is the order of magnitude of the temperature?

Thank you !

 

[CrazyNinja]

What are N-atomic molecules?

 

[RingNebula57]

What are N-atomic molecules?

Molecules with N atoms

 

[Useful nucleus]

Hello everyone!
I recently read some information about the equipartition theorem and degrees of freedom in thermodinamics. I read that for the linear N-atomic and non-linear N-atomic molecules in order to allow the vibrational degrees of freedom to appear we need a really high temperature.
I was curious , because I didn't find the value, at about what temperature do those degrees of freedom appear , what is the order of magnitude of the temperature?

Thank you !

For a diatomic molecule the vibrational heat capacity reaches the classical limit for tempratures larger than (ħω/k_B) . See for example the first 3 pages of these lecture notes:

http://ocw.mit.edu/courses/physics/...fall-2013/lecture-notes/MIT8_333F13_Lec20.pdf

It is possible to make similar analysis for poly-atomic molecules.