CdSe refinement information:

Space group:		P63mc
lattice a,b:		4.30 Angstroms
lattice c:			7.01 Angstroms
lattice alpha,beta:	90 degrees
lattice gamma:		120 degrees

fract. coordinate Cd:	1/3	2/3	0
U11,U22:		0.020
U33:			0.045

fract. coordinate Se:	1/3	2/3	0.3767
U11,U22:		0.014
U33:			0.209
Qmax:			19.0 Inv. Angstroms
Qdamp:		0.045

Data: CdSe nanoparticle 300K X-ray data obtained from for 6-ID beamline at APS using MAR345 IP detector

GOAL: Another illustrative example of refining structure of a nearly-spherical NP system

TASKS:
1) Set up and run a refinement using a bulk model with wurtzite structure, keeping Qdamp fixed to its starting value.
2) Observe the fit quality and results using a single refinement range of your choice.
3) Repeat the refinement using several different refinement ranges, and observe how the result changes.
4) Now pick a refinement range and stick with it. Carry out two refinements, one with Qdamp fixed to its starting value (0.045), and another one where you vary Qdamp.
5) Observe the differences in the refinement results in these two cases.
6) If the results are dramatically different, think about why is that so
7) Which parameters are correlated in case of Qdamp being allowed to vary?
8) What is the best way to obtain "proper" Qdamp?
9) What is affecting Qdamp when refined on data corresponding to a "bulk" material? 