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Author Topic: Wavelengths due to electric dipole transitions  (Read 2746 times)

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brocq_18

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Wavelengths due to electric dipole transitions
« on: August 17, 2011, 03:53:04 AM »

Hi Chemistry guys, this is a problem I posted in my usual physics forum and had no conclusive result for, so as it encompasses chemistry I thought I'd give it a show here. Hope you can help  :)

1. The problem statement, all variables and given/known data

Having problems with this subject. Given hydrogenic carbon, with binding energies of
490 eV (1s) 857.50 eV (2p) 925.54 eV (3p) 949.36 eV (4p). Find wavelengths of all lines due to electric dipole transitions between the levels. State which you expect to be strongest.

2. Relevant equations

I have extensively looked up electric dipoles in books and online and understand the subject competently, along with the selection rules, however I still cannot seem to progress.

Thanks

Brocq
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brocq_18

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Re: Wavelengths due to electric dipole transitions
« Reply #1 on: August 20, 2011, 04:29:02 AM »

Nothing? ???
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Enthalpy

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Re: Wavelengths due to electric dipole transitions
« Reply #2 on: August 22, 2011, 06:27:55 AM »

I'm not quite convinced the energies are positive, nor does their absolute value increase with the distance to the nucleus...
-490eV would be 1s relative to vacuum for a single electron ("hydrogenic" must be that) around a carbon (-13,6eV*6^2).

Then, transitions emit a photon that takes the energy difference between the orbitals. A re-subtle conversion should give you nm or THz from eV.

Not every transition is allowed. To emit a photon, the orbitals shall differ by the corresponding momentum. 2s -> 1s is forbidden for instance, but others may just require a less probable orbital relative orientation.
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