Diffraction orders of grazing incidence

Hamedo
Messages
1
Reaction score
0

Homework Statement


We have a honeycomb lattice. There is an incident wave of 400 nm, whose wavevector has an angle of 75 degree with the surface's normal. This problem is similar to LEEDS ( low energy electron diffraction).

Homework Equations


What is the condition of diffraction i.e. which orders achieve Von-Laue conditions ?

The Attempt at a Solution


I tried to put that |G_2d|<=2*|k_s|, where G is the 2-dimension reciprocal lattice vector, and k is the length of the scattering wavevector ( |K_incidence|=|K_scattering|).
 
Physics news on Phys.org
hmm that's interesting, did you take into account the lattice surface structural constant into account?
 
Hi, I had an exam and I completely messed up a problem. Especially one part which was necessary for the rest of the problem. Basically, I have a wormhole metric: $$(ds)^2 = -(dt)^2 + (dr)^2 + (r^2 + b^2)( (d\theta)^2 + sin^2 \theta (d\phi)^2 )$$ Where ##b=1## with an orbit only in the equatorial plane. We also know from the question that the orbit must satisfy this relationship: $$\varepsilon = \frac{1}{2} (\frac{dr}{d\tau})^2 + V_{eff}(r)$$ Ultimately, I was tasked to find the initial...
The value of H equals ## 10^{3}## in natural units, According to : https://en.wikipedia.org/wiki/Natural_units, ## t \sim 10^{-21} sec = 10^{21} Hz ##, and since ## \text{GeV} \sim 10^{24} \text{Hz } ##, ## GeV \sim 10^{24} \times 10^{-21} = 10^3 ## in natural units. So is this conversion correct? Also in the above formula, can I convert H to that natural units , since it’s a constant, while keeping k in Hz ?
Back
Top