Atomic Form Factor: Finding f(|G|) with λ & θ

  • Thread starter Thread starter anon134
  • Start date Start date
  • Tags Tags
    Atomic Form
Click For Summary
SUMMARY

The discussion focuses on calculating the atomic form factor, f(|G|), for a uniformly distributed negative charge over a sphere of radius R. The equation f(|G|) = ∫₀^{∞} ρ(r) e^{i \vec{G} \cdot \vec{r}} dr is utilized, with ρ(r) defined as -Q δ(r-R). The relationship between f(|G|) and the scattering angle θ is explored, leading to the expression f(|G|) = -Q e^{i |G|R cos(θ)}. The challenge presented is the interpretation of the resulting imaginary component of the form factor.

PREREQUISITES
  • Understanding of atomic form factors in scattering theory
  • Familiarity with spherical coordinates and delta functions
  • Knowledge of complex numbers and their applications in physics
  • Basic principles of x-ray scattering and wave functions
NEXT STEPS
  • Study the derivation of atomic form factors in more complex geometries
  • Learn about the implications of complex form factors in scattering experiments
  • Explore the role of scattering angles in determining material properties
  • Investigate the use of Fourier transforms in physics applications
USEFUL FOR

Students and researchers in physics, particularly those focusing on crystallography, materials science, and x-ray scattering techniques.

anon134
Messages
4
Reaction score
0

Homework Statement


1. Let -Q charge be uniformly distributed over a sphere radius R. Find f(|\vec{G}|), the atomic form factor.
2. Let the incident xrays have wavelength \lambda, determine the dependence of f(|\vec{G}|) on \theta, the scattering angle.

Homework Equations



f(|\vec{G}|)=\int_0^{\infty} \rho(r) e^{i \vec{G} \cdot \vec{r}} dr


The Attempt at a Solution



\rho(r) = -Q \delta (r-R)

\vec{G} \cdot \vec{r} =\vec{G} \cdot r \hat{r} = |G||r| cos(\theta)

f(|\vec{G}|)=\int_0^{\infty} -Q \delta (r-R) e^{i |G|r cos(\theta)} dr

My instinct would be just to say:

f(|\vec{G}|)=-Q e^{i |G|R cos(\theta)}

But this leaves the term to be imaginary. Any ideas?
 
Physics news on Phys.org
anyone have any thoughts?
 
Well, your calculation is correct from what I can see. What is the problem with an complex form factor?

Torquil
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
1
Views
2K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 8 ·
Replies
8
Views
12K