What's the difference between Bragg spacing, d-spacing, Q and repeat distance?

[thearny]

bragg spacing? how does it differ from d-spacing? and where does q fit in? And finally are all of these directly related to the repeat distance?

 

[thearny]

Does anybody know a good source for information on the basics of X-ray scattering, my library has nothing since 1965, and that's unreadable!

 

[inha]

Cullity: Elements of x-ray diffraction. 1st ed. came out in 1955 and it's still very useful. Latter editions are useful too but if your library doesn't have them you better be loaded because they're expensive. Als-Nielsen, McMorrow: Elements of modern x-ray physics is good too.


bragg spacing and d-spacing? I'm unfamiliar with this terminology. I suppose they mean lattice plane spacing in direct and reciprocal spaces but in which order? repeat distance means lattice plane spacing too I think.

q is the scattering vector. the difference between the incident and diffracted beam. it is related to the lattice spacing via the Laue diffraction conditions

$$q \cdot a=2\pi h$$
$$q \cdot b=2\pi k$$
$$q \cdot c=2\pi l$$

where q is the scattering vector, a,b and c the lattice vectors in direct space and h,k and l the miller indices of the plane the beam is getting scattered from.

quite a few solid state physics books also have pretty good basic explanations of x-ray diffraction.