Re: a question from an AP Chem student...

[Ludwik Kowalski <kowalskiL@Mail.Montclair.edu>]

Donald Simanek asks:

> ...How does particle receive information that the interaction is a
"go"? If the
> energies aren't matched, the interaction doesn't happen. Presumably
the
> interaction is a substantial "event". What mechanism of interaction
between
> the approaching particles sets the stage for the even to happen. An
event can't
> happen until the participating entities "know" (receive physical
> stimuli/information) from each other.

Here is one point of view. According to dE*dt>h, where dE is a "spread"
in
energy corresponding to a "time duration" dt. If dt is very small then
dE is very
large. Thus at very short time intervals the "energies mismatches" do
not count
and the system can distinguish between final outcomes which are possible
and
impossible. I do not think that "mechanisms" by which exchanges of
information
occur at very short dt (for example, time during which a distance
covered by a
photon is much shorter than the size of a nucleon) have been
investigated.