Abstract
IN the determination of crystal structure by means of X-ray diffraction, data, the Fourier method1 has long enjoyed the foremost place. Attempts have been made to substitute purely analytical techniques2 depending upon either (a) the direct solution of the structure factor equations: where ƒr is atomic scattering factor of rth atom, θr is 2π(hxr/a + kyr/b + lzr/c), (xryrzr) are co-ordinates of the rth atom, and the summation extends over all atoms in the unit cell; or (b) by means of a process3 which attempts to minimize the difference between some non-negative sum function of the difference between the observed structure factor amplitudes and those calculated on the basis of an assumed approximate structure, for example: |F0| and |Fc| being respectively the observed and calculated structure amplitudes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have