I General Questions

II Global Optimization

III Crystal Modelization

Diffraction data

General questions

My question is not answered here !

How can I get news about the evolution (new releases etc..) of Fox ?

What is an "Object" ?

II Global Optimization

I know 'Simulated Annealing' (SA), why do you recommend to use "Parallel Tempering" (PT) ?

My optimization has reached [enter cost here]. Has it converged enough ?

Fox does not optimize profile/unit cell parameters, even if I check the parameters to be optimized ! Why ?

What parameters can/should I optimize ?

What objects should I add in the Optimization object ?

How can I remove an object from an Optimization ?

III Crystal Modelization

How can I take into account Special Positions ? What is the Dynamical Occupancy Correction ?

What happens when two atoms are completely overlapping ? Does one disappear ?

How can I ensure that the algorithm keeps the correct formula for my compound ?

How can I use an Antibump criterion ? How can I see the Antibump parameters ? Does it prevent the "merging" of atoms using the Dynamical Occupancy Correction ?

Should I restrict the positionnal parameters (fractionnal coordinates) to (0;1) using the parameter's limits ? Same for angles in (0,2pi)?

IV Diffraction data

I copied the powder pattern 2theta zero (shift) from my profile fitting program, but it looks wrong ?

How can I change the powder pattern background points ?

Is it possible to exclude parts of a powder pattern ? Can I remove an exclude region ?

NOTE: the powder patterns in these regions are still computed, so if you want to avoid computing the higher parts of the powder pattern, rather use the "Max sin(theta)/lambda" entry field.

Can I use several data sets to refine a single crystal structure ?

You recommend to use only low-angle data, but why discard this information ? High-angle reflections are important for structure determination !

What shall I put in the "linear polarization rate" field ?

Do you take into account the magnetic scattering of neutrons ?

The Rwp and graphs look fine, but the optimized preferred orientation parameters are wrong !

None: FAQ (last edited 2008-03-08 23:02:47 by localhost)