The intense laser-atom physics and ionized electron

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Discussion Overview

The discussion revolves around the phenomenon of intense laser-atom interactions, specifically focusing on the behavior of high-energy electrons ejected from atoms under laser influence. Participants explore the timing of electron ionization, the parameters of the laser, and the implications of electron velocity and energy in this context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants reference Corkum’s work, suggesting that electrons do not ionize immediately but remain near the ion for one or more laser periods, raising questions about the reasons for this behavior.
  • Questions are posed regarding the period of the laser and its parameters, with some participants providing specific values for amplitude and angular frequency.
  • Participants discuss the energy levels of the ejected electrons, noting variations such as 0.1 a.u., 0.3 a.u., and 0.5 a.u., and express uncertainty about the relevance of these values to the problem.
  • A calculation is presented estimating the velocity of the electron based on its energy, leading to a discussion about the time it would take for the electron to leave the atom, which is suggested to be on the order of the laser's period.
  • There is a suggestion that the size of the atom is not well-defined, with varying estimates proposed by participants.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the calculations and the definitions of parameters, indicating that multiple competing perspectives remain without consensus on the interpretation of the Corkum paper or the significance of the findings.

Contextual Notes

Participants note that the definitions of laser parameters and atomic size are not universally agreed upon, which may affect the interpretations of the results and calculations presented.

xylai
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In the intense laser-atom physics, atom can eject high energy electron.
Corkum’s work (PRL 71 1994 (1993)) says that the electron is not ionized immediately. Rather it stays in the vicinity of the ion for one or more laser periods.
I don’t know why the electron stays there for a while and why it is not ionized directly? Can you show me other reports about it?
Best wishes!
 
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what is the period of the laser?
 
olgranpappy said:
what is the period of the laser?

The paper does not give the parameters of laser. The parameters I used are E0=0.1 a.u. and w=0.2 a.u. (E0: the amplitude; and w: angular frequency)
 
and what is the velocity of the "high energy electron"?
 
olgranpappy said:
and what is the velocity of the "high energy electron"?

The energy of the the "high energy electron" is 0.1a.u., or 0.3 a.u., or 0.5 a.u.,...
But most of the electron have the energy 0.1a.u.
I don't know why you need know these values and how they help us solve the problem?
 
xylai said:
The energy of the the "high energy electron" is 0.1a.u., or 0.3 a.u., or 0.5 a.u.,...
But most of the electron have the energy 0.1a.u.
I don't know why you need know these values and how they help us solve the problem?

So, assuming that a.u. means "Hartree atomic units" then the energy of the electron is
[tex] v^2/2 \sim 0.1 {\rm a.u.}\;,[/tex]
and the velocity of the electron is
[tex] v\sim0.4 {\rm a.u.}\;.[/tex]

Then, since the size of an atom is about
[tex] 3 {\rm a.u.}\;,[/tex]
the time it takes the electron to "leave the atom" is about
[tex] 3/0.4\sim 7.5 {\rm a.u.}\;.[/tex]
This is on the order of the period of the laser. Right?

Maybe this is all that the Corkum paper means by their statement.
 
olgranpappy said:
So, assuming that a.u. means "Hartree atomic units" then the energy of the electron is
[tex] v^2/2 \sim 0.1 {\rm a.u.}\;,[/tex]
and the velocity of the electron is
[tex] v\sim0.4 {\rm a.u.}\;.[/tex]

Then, since the size of an atom is about
[tex] 3 {\rm a.u.}\;,[/tex]
the time it takes the electron to "leave the atom" is about
[tex] 3/0.4\sim 7.5 {\rm a.u.}\;.[/tex]
This is on the order of the period of the laser. Right?

Maybe this is all that the Corkum paper means by their statement.

Maybe your method is right.
But the period of the laser is 2*pi/w=31.4a.u. So I need consider this problem deeply.
Thank you for your kindly reply.
:smile:
 
xylai said:
Maybe your method is right.
But the period of the laser is 2*pi/w=31.4a.u.
So I need consider this problem deeply.

You could consider that the "size" of the atom was never well defined and may as well be taken as 10 or 20 atomic units.

Thank you for your kindly reply.
:smile:

You're welcome. Good luck solving your problem. Cheers.
 

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