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Ionization Energy (Quantum Mechanics)

  • Thread starter vcollier
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Homework Statement



When ultraviolet radiation of wavelength 58.4 nm from a helium lamp is directed on to a sample of krypton, electrons are ejected with a speed of 1.59 Mm/s. Calculate the ionization energy of Krypton.


Homework Equations



E=hv, [itex]\frac{1}{λ}[/itex]=R(1- [itex]\frac{1}{n2}[/itex] ) <- Lyman series
Ionization energy = [itex]\frac{hcR}{n2}[/itex]

The Attempt at a Solution



I used the Lyman series to try and find the Rydberg constant for Krypton (with n=4), then substituted that value into the Ionization energy equation with n = 4 again. I'm given that the answer should be 14 eV, but I didn't get that result.

My confusion is how these equations relate to the ionization of krypton since the equations assume a single electron atom, which krypton is not. Furthermore, I can't find a use for the velocity (E= 0.5mv2 also doesn't give the correct answer).

Any help in figuring out how to approach this problem would be greatly appreciated.
 

Answers and Replies

  • #2
6,054
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Why do you care about the structure of krypton's spectrum? You have the energy of incident photons, you have the energy of emitted electrons. Where is the difference at?
 
  • #3
TSny
Homework Helper
Gold Member
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The Lyman type of series only applies to one-electron atoms or ions. Try relating this problem to the photoelectric effect.
 

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