Quote:
Originally Posted by bojan
Steven,
Perhaps the Hydrogen atom is a bad example to highlight your point.
If we assume (or accept the "crazy" idea) that electron is a wave (de Boglie) , then it is very easy to see why we have different energy levels here.. because when the wave goes around the nucleus, the only possible orbits are those where the circumference of the orbit is the integer multiple of the electron wavelength. So the distances (and therefore energy levels, calculated from them, taking into account the electric charge and the attracting force between proton and electron) are strictly determined. And the measurements (spectrum) show excellent agreement with calculation results.
The problem are other, heavier atoms, where things are not so simple and the energy levels calculated using this simple "mechanistic" model are far from what is measured in experiment. This is because many other things affect the results, Pauli's principle is just one of those, which simply does not play any part in Hydrogen atom affairs (because there is only one electron here and we need more electrons for this principle to become a factor at all).
Otherwise, your point is very valid :-)
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Thanks for your comments.
What you're describing was an early model of quantum mechanics for the hydrogen atom which was still very much influenced by classical mechanics. It's one of those unfortunate cases of a model that turned out to being completely wrong despite giving the right answers
. Due to the Heisenberg uncertainty principle, electrons don't travel in orbits but exist as probability densities. It's not possible to make specific measurements about the position or momentum of an electron.
The success of quantum mechanics for describing the hydrogen atom was based on expressing the electron as a mathematical wave function.
Using this model quantum mechanics was able to reproduce Balmer's formula for the position of the emission and absorption lines in the hydrogen spectrum.
This leads me back to my original point that Quantum mechanics was built on observation rather than a specific attempt to explain mechanisms.
Regards
Steven