 
 PHY.K02UF Molecular and Solid State Physics  
In the range of scattering vectors between 0 < q < 25 Å^{1}, the atomic form factor is well approximated by the expression, [1]
$\large f(q) \approx \sum\limits_{i=1}^{5} a_i\exp\left(b_i\left(\frac{q}{4\pi}\right)^2\right),$
where the values of $a_i$, and $b_i$ are tabulated below. The different atomic form factors for the elements can be plotted using the form below.

Element  a_{1} 
b_{1} 
a_{2} 
b_{2} 
a_{3} 
b_{3} 
a_{4} 
b_{4} 
a_{5} 
b_{5} 
[1] The electron atomic form factors were taken from the International Tables for Crystallography: http://it.iucr.org/Cb/ch4o3v0001/sec4o3o2/.