On Mon, Sep 8, 2014 at 12:22 AM, Andreas Förster <docandreas@gmail.com> wrote:

I've solved a structure from a SAD dataset collected at 1.54 Å. The structure contains a good number of sulfurs and also what I think is a potassium ion.

You could try the ion identification feature: place_ions=K wavelength=1.54

I thought I'd get close to the book values for S and would be able to identify the other anomalous scatterer by the refined f'/f" values. Naiveté or stupidity?

Naiveté, I guess. It's definitely not as accurate as Phaser's refinement of f'', for reasons that are beyond my understanding. Part of the problem is the correlation with occupancy and B-factor - especially f', which will tend to soak up any errors in occupancy and/or scattering power.

-Nat