Orientation of Lowest Energy Photons from Hydrogen

[HarryWertM]

What is the orientation of a photon emitted by an atom? By orientation, I mean the direction of the photon's travel relative to the orbital axis of the electron. Consider only the lowest energy photons from Hydrogen atoms. I am sure I would not understand anything more complex.

 

[HarryWertM]

OK, my own best answer... There are no "planar" orbits in modern atomic theory which might - might, as far as I know - be the "standing wave model" in which there is no way to define an orbital axis and thus no orientation for an emitted photon.

This leaves much for a civilian to wonder about. In particular, I read somewhere - don't ask where - that the lowest energy wave function for a hydrogen electron oscillates back and forth directly through the nucleus. This obviously defines an orientation which in turn might define some experimental observables for photon absorption. Like in frozen hydrogen? What kinds of results can be predicted if a sample of frozen hydrogen is zapped in the new attosecond x-ray laser at SLAC?

Behind this particular subject is the more sense of just how much "reality" there is in modern physics. There seems no end to experimental phenomena of uncertain predictability as well as no end to new theories. Does anybody really understand anything?

 

[lightarrow]

What is the orientation of a photon emitted by an atom? By orientation, I mean the direction of the photon's travel relative to the orbital axis of the electron. Consider only the lowest energy photons from Hydrogen atoms. I am sure I would not understand anything more complex.

There isn't, it's indeterminate. If you measure the atom's recoil, *then* you can say that the photon took the opposite direction (entanglement), but with many repetitions of the experiment you would find all possible directions.

 

[The_Duck]

Photons get emitted when electrons in atoms transition from higher energy states to lower energy states. There are many different transitions an atom can undergo depending on which energy state it starts in. Photons emitted in a given transition are more likely to go in some directions than others. As you note, for one direction to be more probable than another requires something to pick out a special direction--this is done by the angular momentum of the atom, which points in a certain direction (even though the electrons don't have well-defined "orbits").

There seems no end to experimental phenomena of uncertain predictability as well as no end to new theories. Does anybody really understand anything?

Quantum mechanics is very well understood. It simply predicts probabilities instead of certainties when you measure certain quantities, and gives mathematical reasons why this is the best you can do. Certainly there are plenty of theories about many poorly-understood phenomena, but as http://blogs.discovermagazine.com/cosmicvariance/2010/09/23/the-laws-underlying-the-physics-of-everyday-life-are-completely-understood/" points out, "the laws underlying the physics of everyday life are completely understood."