There is some fundamental about effective mass that I am misunderstanding about effective masses.(adsbygoogle = window.adsbygoogle || []).push({});

I understand the relation

[itex]E\left(k\right) = E_0 + \frac{1}{2m^*}k^2[/itex]

But I'm not sure when it's appropriate to fit this to a parabola.

I would have thought the fitting is only done when you have an independent-particle model, and know the energies associated with each k "orbital".

The data I have is a parabola of energies built by systematically adding electrons and calculating the corresponding Hartree-Fock energy.

For example, the minimum of my data is the HF energy of n electrons. The next point is the HF energy of n+1 electrons. The next point is the energy of n+2 electrons. So these points, strictly speaking, aren't energies of k values. I was told I can still fit this data to a parabola and derive an effective mass. The data fits a parabola shape very well, but I am assuming I can't simply use the above equation, as my energies are N-electron energies and no "k number" energies. Or can I?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Derivation of Effective Mass from a Parabola

Can you offer guidance or do you also need help?

**Physics Forums | Science Articles, Homework Help, Discussion**