Selection rules in electron transitions

AI Thread Summary
The discussion centers on the selection rules for electron transitions during photon absorption and emission. It explores how electrons can transition between energy levels, specifically detailing the allowed transitions based on their quantum states. The user proposes that an electron can transition from various states, such as from ns to mp or from np to ms or md, but emphasizes that moving up a shell does not determine the specific orbital transitions within the spdf categories. Two hypothetical electrons, Alice and Bob, are used to illustrate the concept. Alice transitions through multiple shells, while Bob jumps directly to a higher shell, leading to different possible final states for each. The discussion raises the question of whether both electrons can end up in the same state and seeks clarification on the reasoning behind the selection rules. Additionally, it inquires about the role of photon polarization in relation to these rules. The user acknowledges the complexity of selection rules and expresses gratitude for resources that provide further insight into the topic.
nomadreid
Gold Member
Messages
1,748
Reaction score
243
TL;DR Summary
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.
 
Chemistry news on Phys.org
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
 
  • Like
Likes Twigg and nomadreid
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.
 
It seems like a simple enough question: what is the solubility of epsom salt in water at 20°C? A graph or table showing how it varies with temperature would be a bonus. But upon searching the internet I have been unable to determine this with confidence. Wikipedia gives the value of 113g/100ml. But other sources disagree and I can't find a definitive source for the information. I even asked chatgpt but it couldn't be sure either. I thought, naively, that this would be easy to look up without...
I was introduced to the Octet Rule recently and make me wonder, why does 8 valence electrons or a full p orbital always make an element inert? What is so special with a full p orbital? Like take Calcium for an example, its outer orbital is filled but its only the s orbital thats filled so its still reactive not so much as the Alkaline metals but still pretty reactive. Can someone explain it to me? Thanks!!

Similar threads

Back
Top