Selection rules in electron transitions

In summary, according to the selection rules, an electron can only transition from one energy level to another, up or down, within its shell.
  • #1
nomadreid
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Do the selection rules for electron transitions imply that in photon absorption/emission, an electron can only jump between s and p, or p and d, or d and f? So, e.g., an electron jumping from shell 5 to 6, then from 6 to 7, would end up in a different orbital than an electron jumping directly from 5 to 7?
Not sure if this belongs in Chemistry or Physics.

Even less sure if I understand the selection rules for electron transition correctly; hence this question. So I would be grateful for someone to please correct the following:

Letting n and m be energy levels
An electron that absorbs a photon can only transition in one of the following ways:
from ns to mp,
from np to (ms or md),
from nd to (mp or mf)
from mf to md
and an electron that emits a photon can only transition also in those ways.

Going up a shell does not dictate whether it goes "up" or "down" in the spdf orbitals.

If the above makes any sense, then for example, if
---an electron Alice started in the 5th shell and jumped first to the 6th shell, then to the 7th shell, and
--- another electron Bob started in the 5th shell and jumped directly to the 7th shell,
the possible transitions would be

Alice
5s to 6p to 7d
5p to 6s to 7p
5p to 6d to 7p
5p to 6d to 7f
5d to 6p to 7s
5d to 6p to 7d
5d to 6f to 7d

Whereas Bob:
5s to 7p
5p to 7s
5d to 7p
5d to 7f
5f to 7d

Therefore Alice and Bob would never end up at the same place. Right? If this is correct but the reasoning is different, then why?

Finally: does the polarization of the photon have anything to do with the (correct version of) the selection rules?

Many thanks in advance, with apologies for the conceptual mess.
 
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  • #2
Somewhere I've got this text:
content.png

Selection rules are rather complicated.
Check out this site: https://chem.libretexts.org/Bookshe...f_Atoms/6.03:_Line_Spectra_and_the_Bohr_Model
 
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  • #3
Thanks, dlgoff. Upon your recommendation, I have obtained that book, and found "selection rules" in the index. I shall look into it. Also, the link you sent is a nice summary of the basic theory of transitions.
 
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FAQ: Selection rules in electron transitions

What are selection rules in electron transitions?

Selection rules in electron transitions refer to the conditions that must be met for an electron to undergo a transition from one energy level to another. These rules determine which transitions are allowed and which are forbidden.

What are the main selection rules for electron transitions?

The main selection rules for electron transitions are the conservation of energy, conservation of angular momentum, and conservation of parity. These rules dictate that the energy, angular momentum, and parity of the initial and final states must be the same for a transition to be allowed.

How do selection rules affect the emission spectrum of an atom?

Selection rules determine which transitions are allowed and thus affect the emission spectrum of an atom. Only transitions that are allowed by the selection rules will be observed in the emission spectrum, while forbidden transitions will not be present.

Can selection rules be violated?

Selection rules are based on fundamental principles of quantum mechanics and are generally considered to be unbreakable. However, there are some exceptions, such as the Jahn-Teller effect, where certain molecules can undergo forbidden transitions due to distortions in their structure.

How do selection rules relate to the concept of quantum numbers?

Selection rules are closely related to the concept of quantum numbers. The conservation of energy and angular momentum are linked to the principal and angular momentum quantum numbers, while the conservation of parity is related to the spin quantum number. These quantum numbers must be the same for a transition to be allowed.

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