shapes of potentials!!


by photon79
Tags: potentials, shapes
photon79
photon79 is offline
#1
Nov14-05, 05:48 PM
P: 60
Hi all..

1)we have,for example,rectangular, square well, well type etc potentials. How is the shape of a potential is determined? What is the shape of the nucleus potential?

2)I am unable to get the physical importence of the wave vector 'K' and K-space in band theory!
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Pieter Kuiper
Pieter Kuiper is offline
#2
Nov15-05, 02:29 AM
P: 143
Quote Quote by photon79
1) What is the shape of the nucleus potential?
In light nuclei it as approximately parabolic.

In heavy nuclei (uranium), alpha particles are often modelled as moving in a square well + Coulomb repulsion.
2)I am unable to get the physical importence of the wave vector 'K' and K-space in band theory!
Ask your teacher to explain it one more time.
Kruger
Kruger is offline
#3
Nov15-05, 06:26 AM
P: 219
The wave vector k is identically to: abs(k)=2pi/lambda and momentum=h(bar)k. So you can think of it as the inverse of the wave length of a wave. Its more confortable to write psy(x)=exp(kx) than psy(x)=exp(2pi/lambda*x).
If we work in more dimensions k must be a vector and as you can see in the wave function lambda must therefor also be a vector. And 2pi/VECTOR seems to look strange.

You see?

Claude Bile
Claude Bile is offline
#4
Nov15-05, 05:40 PM
Sci Advisor
P: 1,465

shapes of potentials!!


The k-vector gives the direction of wave propagation. The magnitude of k is proportional to the momentum of the wave, which as we know is related to the wavelength.

Claude.


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