From: "JACK L. URETSKY (C)1998; HEP DIVISION, ARGONNE NATIONAL LAB ARGONNE, IL 60439" <JLU@HEP.ANL.GOV>
Date: Wed, 10 Mar 1999 08:03:57 -0600
Hi all-
John Denker wrote:
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It's true that atoms are high-Q oscillators.
It's true that bigger molecules couple better.
It's true that atomic sizes are small compared to the EM wavelengths that
go with atomic frequencies. Angstroms versus microns.
These facts are true, but the coupling could not be deduced from size
alone. You need to think about electron charge, electron mass, and various
other things.
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I'm thoroughly enjoying John's characterizations of atomic radiation
and am unable to resist the temptation to throw in a couple of hints:
1. The "Q" of an oscillator is essentially the frequency divided
by the linewidth. I assume John wants us to think about the natural Q
of the resting atom.
2. The linewidth is, of course, the inverse of the lifetime
associated with the transition. Aha! Q measures the length of the
train of waves radiated.
3. It is sufficient to imagine that we are only discussing
dipole transitions. In order to understand how atomic size enters
the picture it helps to know a bit of quantum mechanics.
Thanks John,
Jack
"I scored the next great triumph for science myself,
to wit, how the milk gets into the cow. Both of us
had marveled over that mystery a long time. We had
followed the cows around for years - that is, in the
daytime - but had never caught them drinking fluid of
that color."
Mark Twain, Extract from Eve's
Autobiography