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-----Original Message-----
From: phys-l@lists.nau.edu: Forum for Physics Educators
[mailto:PHYS-L@lists.nau.edu]
Sent: Tuesday, September 19, 2000 8:29 AM
To: PHYS-L@lists.nau.edu
Subject: Re: Collisional excitations
Franck-Hertz, eh? I'd heard of it but never read the experiment.
Thank you all for your comments.
Philip Zell
______________________________ Reply Separator
_________________________________
Subject: Re: Collisional excitations
Author: "phys-l@lists.nau.edu: Forum for Physics Educators"
<PHYS-L@lists.nau.edu> at internet
Date: 9/19/00 5:03 AM
That is right. Positive energy values as those of the
exciting particle
are not quantised. They are continuous.
regards,
Sarma.
They are continuous.
At 04:20 PM 9/18/00 -0400, you wrote:
lessons of the-----Original Message-----
From: phys-l@lists.nau.edu: Forum for Physics Educators
[mailto:PHYS-L@lists.nau.edu]On Behalf Of Joel Rauber
Sent: Monday, September 18, 2000 3:23 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Collisional excitations
Isn't quantization of energy during collisions one of the
_absorbed_Franck-Hertz experiment?
Joel Rauber
Yes--Franck_Hertz is evidence of the quantization for the energy
by the target atoms, but does not show that the initial energy of thetransition, there
incident electron is quantized. As long as the incident electron has
sufficient energy to cause the target atom to make the
is
a non-zero probability for the interaction to take place.The probability
is
measured using the concept of cross section.rises fairly
The plot of cross section vs. incident electron energy is known as an
excitation function. That function always starts at zero,
quickly, and then drops off at various rates, typicallybetween 1/E and
1/E^3 at high energies. The slope of the high energy enddepends on the
particular transition being induced in the atom.excitation of
(My thesis title was something like "The electron impact
krypton and xenon.")
--
John E. Gastineau john@gastineau.org
140 Tenderfoot Road (301) 387-8494
Oakland MD 21550-6957 (301) 387-8495 fax
USA http://gastineau.org