Quantum electrodynamics

[ANTARES1_1]

Hello everyone,

I was just having a small doubt.

What determines the energy(wavelength) with what the photon will be emmited from an electron? Is there an equation or something or is it a specific value?

[Zermelo]

It depends what the electron is doing to cause the photon to be emitted.

For example, if it is moving down the energy levels in an atom, then the difference between the "from" and "to" levels is the energy of the emitted photon (which then determines its frequency, via E=hf, and hence its wavelength).

[ANTARES1_1]

But what if you don't have the f?

[Clarkey]

39 minutes ago, ANTARES1_1 said:

Is there an equation or something or is it a specific value?

You can look them up as an emission spectrum as they are all constants. There probably is a complex method of working it out (I have distant memories of Schroedinger's equation for atom orbits) - but maths was never my strongest suit.

[saac]

22 minutes ago, ANTARES1_1 said:

But what if you don't have the f?

What information do you have?

[ANTARES1_1]

I know that if you have been given the wavelength the you can use the formula E=hc(lambda). But I wanted to know what to do when f is not given in the above given formula

6 minutes ago, saac said:

What information do you have?

 

[saac]

1 minute ago, ANTARES1_1 said:

I know that if you have been given the wavelength the you can use the formula E=hc(lambda). But I wanted to know what to do when f is not given in the above given formula

 

You determine f from the wavelength. If you do not have the wavelength then you simply divide the electron transition energy difference by Planck's constant as per @Zermelo post above and this will give you the frequency. 

Jim 

[ANTARES1_1]

Yes, soon figured it our.

Thanks for the reply Jim.

[Clarkey]

1 hour ago, ANTARES1_1 said:

Yes, soon figured it our.

Thanks for the reply Jim.

In case you're interested there are some articles all about emission spectra.

Articles | Webb (webbtelescope.org)