Q value

A given q value (momentum transfer in reciprocal-space) corresponds to a real-space distance (d) of:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle q = \frac{2\pi}{d} }

Thus, from a peak position in scattering, one can calculate the realspace repeat-structure distance:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle d = \frac{2 \pi}{q} }

One must be careful, however. A peak in reciprocal-space corresponds to a repeating structure in the realspace lattice; i.e. this may or may not correspond directly to particle-particle spacings.