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Re: Collisional excitations



I haven't been following this discussion closely, so my apologies if I
repeat something that already has appeared here.

My understanding is that the Franck-Hertz experiment is not only an example
of quantization during collisions, but at the time it was perhaps the only
non-spectroscopic example of quantization. My understanding is that a
non-spectroscopic example of quantization was a primary goal of Franck and
Hertz.

Additionally, if not already mentioned, the study of the temperature
dependence of heat capacities is also an example of collisional energy
quantization. It does not lead to a "sharp" result like the F-H experiment,
but it explains why the apparent degrees of freedom (and hence the heat
capacity) change as the temperature changes. If collisional energies are
not sufficient to supply the rotational quantum gap, then rotational degrees
of freedom, i.e. rotational energy, cannot contribute to the heat capacity.
Likewise for vibrational quantization.


Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817