X-ray diffraction; atomic form factor

In summary, the conversation discusses the atomic form factor of an fcc lattice of Buckyballs (C60 atoms) and the explanation for the weaker (2,0,0) X-ray diffraction peak compared to the (1,1,1) peak. The person is struggling to calculate the form factor and is asking for help with the vectoric expression.
  • #1
physics_fun
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0
Hey,

I'm working on a problem about the atomic form factor. I found that the atomic form factor of an fcc lattice of Buckyballs (C60 atoms) looks like f~(sin(Gr))/G multiplied bij some constants.

The question is now to explain from this atomic form factor why the (2,0,0) X-ray diffraction peak is much weaker (compared, for example, to the (1,1,1) peak).

I tried to put the numbers in, but every time I try this, I get (almost) the same answers for the two peaks...:(

What am I doing wrong?

edit: r=constant
 
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  • #2
that is because, 002 is at an higher 2theta value, if you look at braggs law you can see that the d spacing is invers related to theta. Bigger miller index, means smalle d-spacing which in turns meens a larger theta value. And as the form factor falls of with bigger theta values, that is the explanation..
 
  • #3
Hey!
Can u explain how did you calculate the form factor?
I don't know how to pass from the vectoric experession to an expression I'll be able to calculate..
tnx alot!
 

1. What is X-ray diffraction and how is it used in scientific research?

X-ray diffraction is a technique used to study the structure of crystalline materials. It involves shining a beam of X-rays onto a crystal and measuring the patterns of diffracted beams that are produced. This can provide information about the spatial arrangement of atoms within the crystal lattice, which is essential for understanding the physical and chemical properties of materials.

2. What is the atomic form factor in X-ray diffraction?

The atomic form factor is a measure of how strongly an atom scatters X-rays. It takes into account the size, shape, and electron density of the atom, and is used in the calculation of the intensity of diffracted beams in X-ray diffraction experiments.

3. How is the atomic form factor determined?

The atomic form factor is determined through a combination of experimental measurements and theoretical calculations. The electron density of an atom can be calculated using quantum mechanics, and this information is then used to determine the atomic form factor.

4. How does the atomic form factor vary for different elements?

The atomic form factor varies for different elements due to differences in their electron density and atomic structure. Heavier elements with more electrons tend to have a higher atomic form factor than lighter elements, and the form factor also varies with the angle of diffraction and the energy of the X-rays used.

5. What are the practical applications of X-ray diffraction and atomic form factor?

X-ray diffraction and atomic form factor have a wide range of practical applications in fields such as materials science, chemistry, and biology. They are used to determine the structure of molecules, study the properties of crystals and polymers, and investigate the atomic arrangement in biological molecules. This information can be used to design new materials, understand the mechanisms of chemical reactions, and develop new drugs and treatments.

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