PS: An interesting question: why do no spell checkers recognise 'orbitals' as being a word, when it is very suggestive that it should have a plural from its grammatical structure?
Monday, April 16, 2012
A&M on the Electron in a Weak Potential
A&M go through this topic in a slightly different way to Dr Paul's lecture notes. The description of the approximation part of the text has two main sections, the second of which (Bragg plane example) is analogous to the lecture notes. The first section essentially justifies us looking only at the near-degenerate atomic orbitals (the two orbitals from different atoms that are similar in energy)—this is because the other energy levels are not shifted by much when compared to the shift in the near-degenerate orbitals—and continues to explain the near degenerate case (the result of this bit is partially in the lecture notes). The second section then uses this to describe the case where two near-degenerate free electron orbitals are distanced from the other energy levels, as in the notes.
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Will give a serious comment later, but
ReplyDeletehttp://www.phdcomics.com/comics/archive.php?comicid=1437
&gamma
ReplyDeleteAnother case of misspelling?
Also on the different styles/notation/vocab:
ReplyDeleteI think the Solid State Simulations refer to the Weak Periodic Potential as Nearly Free Electron.
Tight Binding is still Tight Binding ☺
Simulations book explains WPP clearly too
DeleteEverything we did in class make more sense when I read the initial section of the book. The largest shift/correction to the free electron energy is quadratic to U for the case of no nearby degenerate levels but is linear to U for degenerate levels so the correction is most important for the degenerate case (as Josh pointed out). This leads to an important observation, WPP(this is catchy) affects the free electron energy levels the most for wave vectors whose tip lies on the Bragg plane.
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