Amplitude and inter atomic separation

1. Dec 23, 2011

ibysaiyan

1. The problem statement, all variables and given/known data
The question goes something like this:
What % of inter atomic separation is the root mean amplitude.
The data given is:
Inter atomic separation : 0.29nm , T =300k , D = 20 N/m , Aluminium atomic weight 27 g/mole.
How do I proceed I have no idea on how to relate mean inter atomic separation and rms of the amplitude.

2. Relevant equations

Formula to calculate Root mean amplitude is : √KbT/D

3. The attempt at a solution

As above.