Photoelectric effect and metal's delocalised electrons

Click For Summary

Discussion Overview

The discussion revolves around the photoelectric effect, specifically regarding the role of delocalized electrons in metals and the implications of using high-energy photons, such as x-rays and gamma rays, in this context. Participants explore the nature of electrons ejected during the photoelectric effect and the boundaries of the experiment's scope.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant, Glenn, questions whether the ejected electrons in the photoelectric effect are primarily from the conduction band (delocalized electrons) rather than valence electrons, suggesting that high-energy photons could lead to ionization events instead.
  • Another participant emphasizes that using x-ray photons may be outside the traditional scope of the photoelectric effect, which typically involves metals and UV sources.
  • A different participant agrees with the notion that the photoelectric effect is primarily associated with metals and suggests comparing the work function to the k-band energy.
  • One participant clarifies that the standard photoelectric effect is conducted on metals using UV sources, indicating that the emitted photoelectrons originate from the conduction band, but notes that photoemission spectroscopy encompasses a broader range of techniques, including those that probe deeper electron levels.
  • Another participant expresses interest in the connection between the photoelectric effect and photoemission spectroscopy, indicating a desire for further exploration of the topic.

Areas of Agreement / Disagreement

Participants exhibit some agreement regarding the traditional scope of the photoelectric effect being limited to metals and UV sources. However, there is disagreement about the implications of using higher-energy photons and the nature of the electrons involved, indicating that multiple competing views remain.

Contextual Notes

There are limitations regarding the assumptions made about the types of electrons involved in the photoelectric effect and the definitions of the phenomena being discussed. The discussion does not resolve the implications of using different photon energies or the boundaries of the photoelectric effect versus photoemission spectroscopy.

Glenn G
Messages
113
Reaction score
12
Hi all,
With the photoelectric effect is it the 'sea' of free electrons that are ejected if the photons are above threshold frequency (i.e. Conduction band electrons ) rather than valence electrons ? If say very energetic gammas are used then suppose this could knock out valence electrons but guess that is then just normal ionisation events ?
Is this thinking correct?
Would really appreciate any thoughts.
Glenn.
 
Physics news on Phys.org
If you are going to start exposing metals to say x-ray photons I think you have stepped outside the scope of the PE effect experiment.
 
houlahound said:
If you are going to start exposing metals to say x-ray photons I think you have stepped outside the scope of the PE effect experiment.
It seems to only talk about photoelectric effect in connection with metals and not non-metals so that made me think it might be delocalised electrons that are released.
 
houlahound said:
If you are going to start exposing metals to say x-ray photons I think you have stepped outside the scope of the PE effect experiment.
Interesting thought thanks for that
 
The "standard" photoelectric effect is (i) done on metals and (ii) uses, at most, UV sources. So the photoelectrons emitted are from the conduction band.

Now it doesn't mean that this phenomenon hasn't changed from that. The overall area is now generally known as photoemission spectroscopy, and it encompasses a huge field. This includes x-ray photoemission spectroscopy (XPS). This technique does probe deeper levels of the material which are usually known as core-levels. Here, it no longer just probe the conduction band, but also electrons that still localized to the atoms making up the material.

Photoemission techniques have also been done on semiconductors and insulators to a certain degree. In fact, most high quantum efficiency photocathodes are made of semiconductors.

Zz.
 
  • Like
Likes   Reactions: Glenn G and vanhees71
That great Zz, I didn't know the link with photoemission. Very interesting. G
 

Similar threads

High School Photoelectric phenomenum can only be proved as a particle effect?
  • · Replies 5 ·
Replies
5
Views
1K
Undergrad Question about the Photoelectric Effect and the Work Function of a Metal
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Photoelectric effect and Saturation Current
  • · Replies 12 ·
Replies
12
Views
2K
High School Why is there now evidence of a lag time in the photoelectric effect?
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad Ejection of Only one electron by a Photon in the Photoelectric effect
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Some questions about the photoelectric experiment
  • · Replies 13 ·
Replies
13
Views
2K
Undergrad Does photoelectric effect include light with threshold freq?
  • · Replies 2 ·
Replies
2
Views
2K
High School Using Interference Principles to Increase the Efficiency of Solar Panels
  • · Replies 0 ·
Replies
0
Views
1K
High School Photoelectric effect and atomic excitation
  • · Replies 3 ·
Replies
3
Views
3K
High School The Mystery of Excited Electrons: Are They Moving Away from the Nucleus?
  • · Replies 2 ·
Replies
2
Views
1K