Absorption of 2 photon by 1 electron in photoelectric effect

Click For Summary
SUMMARY

The discussion centers on the phenomenon of two-photon absorption (TPA) in the photoelectric effect, specifically how it alters the threshold frequency and stopping potential. It is established that the threshold frequency is halved when a single electron absorbs two identical photons, leading to the modified equation ## eV_{0} = 2hf - \phi ##. This indicates that the stopping potential increases for a given frequency due to the energy contribution of both photons. The analysis confirms that the stopping potential ratio is ## \frac{2f - f_0}{f - f_0} ##, illustrating the impact of TPA on the photoelectric effect.

PREREQUISITES
  • Understanding of the photoelectric effect and its equations
  • Familiarity with two-photon absorption (TPA) concepts
  • Knowledge of threshold frequency and stopping potential
  • Basic principles of electromagnetic radiation and photon energy
NEXT STEPS
  • Study the implications of two-photon absorption in various materials
  • Explore the mathematical derivation of the photoelectric effect equations
  • Investigate the role of laser intensity in enhancing TPA
  • Learn about mixed frequency electromagnetic waves and their effects on stopping potential
USEFUL FOR

Physics students, researchers in quantum mechanics, and professionals studying the photoelectric effect and photon interactions in materials.

spaghetti3451
Messages
1,311
Reaction score
31

Homework Statement



In the photoelectric effect, it is assumed that a single electron absorbs a single photon. But, there is a certain probability that a single electron may simultaneously absorb two identical photons from a high-intensity laser. How would such an occurrence affect the threshold frequency, the stopping potential and the equation ## eV_{0} = hf-\phi ##?

Homework Equations

The Attempt at a Solution



The threshold frequency is halved because it is possible to have the most loosely bound electron (with binding energy = work function) absorb the two photons.

The equation ## eV_{0} = hf-\phi ## is modified to become ## eV_{0} = 2hf-\phi ## because hf is the energy of one photon.

Therefore, the stopping potential for a given frequency increases from its corresponding earlier value.Are my answers correct?
 
Physics news on Phys.org
The threshold frequency of any metal on which monochromatic electromagnetic radiation which causes two photon absorption(or interaction) is incident will be half the value of what it would normally be for single photon interactions, which you have correctly evaluated. So the equation ##h(f-f_0) = \frac{1}{2}m_e v^2 = e V_0## becomes equal to ##h(2f-f_0)## where ##f_0 = 2 f_x ## (fx is the threshold frequency for the TPA effect), which is essentially the same as the last equation you came down to in the end. So yes, for E.M. waves with the same frequency, with the TPA effect, you will have a higher stopping potential value.(The ratio of the stopping potentials will be ##\frac{2f-f_0}{f-f_0}## to be precise).
P.S. Let me know if you think there's somewhere I went wrong.
 
Might I add that if there are ##n## photons with distinct energies (##n## frequencies) in a mixed frequency E.M. wave and, hypothetically speaking, if all of them could simultaneously interact with one electron, then the stopping potential would be given by ##eV_0 = h(f_1+f_2+f_3...+f_n -f_0)## , where photoelectric emission just starts happening when ##f_0 = ∑f_i##. The ratio of stopping potentials in this case would be ##\frac{∑f_i - f_0}{f_x-f_0}## where ##f_x## is the frequency of the monochromatic E.M. wave with which we are comparing the mixed frequency wave with. (##f_i## is the set of frequencies in the mixed frequency E.M. wave). I really hope I'm not over-complicating this o0)
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
771
  • · Replies 5 ·
Replies
5
Views
2K
Replies
1
Views
4K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 35 ·
2
Replies
35
Views
4K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K