[joonjae89]

I am trying to use the classical harmonic oscillator to find frequencies of vibration for 1) a diatomic system, and 2) H2O. I am trying to use the procedure outlined by Feynmann (see link below) that uses a mass-weighted force constant matrix. I am having problems, though, and want to understand more.

The dimensions of the matrix - I think - have to do with the number of total degrees of freedom (although I'm not sure why this is). I have no idea how to figure out the values in the matrix. How do I do it?

Feynmann's lectures (see pgs. 13-15):

http://books.google.com/books?id=4YDfQAYrkjkC&pg=PA14&lpg=PA14&dq=%22the+classical+problem+of+vibrations+of+coupled+oscillators&source=bl&ots=1m0IKzqp4z&sig=QzoDXaJJmeL00Rg1Ew17P74GZFc&hl=en&ei=oNqGS-PeMaimtgfM07yvDw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAYQ6AEwAA#v=onepage&q=%22the%20classical%20problem%20of%20vibrations%20of%20coupled%20oscillators&f=false