Vibrational Modes

I think that there is only one concept of 'degrees of freedom'. This is pretty clear from infrared spectra. A water molecule has 3 atoms and so df = 3n - 6 = 3. I found a nice analogy recently for these three. A person's fists are hydrogen and the head is the oxygen. The first mode is the jumping jack motion or boxing someone's ears! A second mode is the one-two punch and the third mode is the push-up.

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Schneider Lab
origin: 2005 Sep 13
updated: 2011 Mar 29

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