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How the heck DOES a molecule absorb 1cm microwaves?



During my crackpot exploits I found some mainstream papers which explain
how a molecule in a cloud of ammonia can absorb the relatively enormous
1cm microwaves ...which is the same conundrum as how a Sodium atom can
absorb 590nM light even thought the atom is around 6000x smaller than the
light's wavelength.

As a student I'd always imagined that light must be different than radio
waves. I thought that, where light was concerned, the single photons must
collide with individual atoms. The truth is quite different, and it shows
that light is the same as RF radiation. The question was answered by
atmospheric physicist Chris Bohren and published in AJP.

One would think that such things had been thoroughly explored back in
1920, but Bohren's paper was in 1983! This seems to be a large hole in
EM theory which was only recently plugged. See the abstract:

http://www.amasci.com/tesla/dipole1.html

Bohren examines small conductive and dielectric beads. Paul/Fischer look
at atoms themselves. I made a couple of diagrams based on the ones in
those two papers:

Poynting vector field surrounding an atom during EM absorbtion
http://www.amasci.com/graphics/dp-absb1.gif

The "effective aperature" of a pointlike resonant antenna
http://www.amasci.com/graphics/dp-absb2.gif

Briefly, the process of light absorbtion is similar to dipole emission run
backwards, but it has one large difference: as a particle absorbs
relatively large waves, the particle becomes an emitter. It sends out a
spherical wavetrain. As a result, we say that the incoming radiation was
partly scattered from the particle, and partly absorbed. We don't realize
that the "scattered" radiation is actually doing the absorbing.

A clearer description is this. In response to incoming waves, the
particle broadcasts an EM wave with identical frequency but with 90deg
phase, and this causes an interference pattern to appear, a pattern where
there is a large node downstream of the particle. The energy missing from
that node doesn't appear in surrounding antinodes. Instead it has
vanished. It ends up inside the particle.

So, how does a tiny particle absorb a big huge wave? Well, how can a tiny
antenna EMIT a long-wavelenght EM wave? Simple: just crank up the
strength of the fields being produced by an antenna, and even the smallest
antenna can broadcast longwave radiation. Or, to pump lots of light
through a tiny pinhole, just blast the pinhole with much brighter light.
The same idea applies to absorbtion: if the tiny antenna produces intense
fields, it will emit long waves, and since the long waves superpose on the
incoming waves, they cause more net absorbtion of energy.

The whole process is a part of conventional antenna physics. However, it
mostly applies to electrically short dipole antennas where a high-Q
resonant circuit has been connected to the antenna. A short resonant
antenna, if the Q-factor of the resonator is very high, will behave like
a much longer 1/2-wave dipole antenna.

So, why does sodium gas block out 590nM light so well? It's because those
atoms are electrically far larger than their diameters. Their "effective
aperatures" are nearly 1000x larger than their physical diameters. But
this only applies to light at the resonant frequency. Off-frequency light
will scatter from the .1nM-diamter atom itself, while light in the sodium
line spectrum "thinks" that the atom is enormous.


PS
What about crackpot stuff? All of the above comes up in two situations:

Low-frequency EM fields cannot affect DNA, etc., because the wavelength
is far too long, so the molecules cannot act as antennas, and the energy
in those photons is far too low to affect chemical bonds.

Nikola Tesla's "broadcast power" cannot have worked because you need
antennas wich are hundreds of miles long if you want to pick up
significant amounts of 5KHz radio waves.

Both of the above statements are misguided. If a biological molecule
should behave like an RLC electric circuit and display resonances at, say
10KHz, it doesn't matter how long the 10KHz wavelength may be. The
molecule will become a strong absorber. And if single molecules should
ever act like macro circuits, multiple-photon absorbtion becomes an issue.

And, if Tesla's receivers contained a resonant circuit connected directly
to a short antenna, that short antenna could intercept the same amount of
energy that would normally require an antenna which was thousands or tens
of thousands times longer. In fact, Tesla's "broadcast power" receivers
were high-Q resonators, not 1/2-wave dipoles.


(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com http://amasci.com
EE/programmer/sci-exhibits science projects, tesla, weird science
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