Exercises 3.3: Atomic form factor

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3.3.1 On the left is the electron density for two atom, green and blue, and on the right is the diffracted intensities from these two atoms. Unfortunately the colors got mixed up in the configure menu.

A) Which atom gave the orange diffraction pattern, and which gave the magenta?

B) What can you conclude from the fact that the peak diffracted intensity from each of the atoms is the same?

C) Given equal peak diffracted intensities, why is the peak electron density for the blue atom less than that of the green?


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3.3.2 This time we have diffraction patterns from two atoms with the SAME rms width of the electron density. Both figures show the SAME diffraction patterns. On the right, the intensity axis has been greatly expanded. One of the atoms has a Gaussian electron distribution, the other a triangular distribution. Again we got the colors mixed up in copying them into the exercise files.

A) What can you say about the total number of electrons in each atom?

B) Of the orange and magenta atoms, which is the Gaussian and which is the triangular?

C) Of the blue and green atoms, which is the Gaussian atom and which is the triangular? The only simple answer we know of to this one is wrong. Can you send us an argument that is correct?