CHEXRAY STRUCTURE MAP

(Modified: March, 2007)

[Standard Queue Procedures]



[Data Collection and Reduction]



[Structure Solution and Refinement]





STANDARD QUEUE PROCEDURES

Fill out a USER WORK ORDER FORM

Attach signed form to the USER QUEUE on the door of 32A Lewis

Wait for your turn in the queue

Remove your form and procede with collection

When finished give the form to Dr. Hollander or place in Data Entry bin

Call next person in queue!



DATA COLLECTION AND REDUCTION

(Back to top of map.)

Sign on in the SMART or APEX Logbook.

MAKE A SUB-DIRECTORY ON THE SMART PENTIUM
(Start SMART from your sub-directory)

Select and mount a crystal.

(Measure your dark frames, center the crystal)
(and take your matrix SCAN. Evaluate crystal quality.)

COLLECT DATA

Transfer data from Pentium to the Linux PC

(GOFTP alows you to login to the smartuse or apexuser accounts on ChexCSD.)
(Create subdirectory and transfer frame data and *.p4p files.)

INTEGRATE DATA with SAINT

(Raw merged data and printed output)

[XPREP/SADABS]
(Convert Data from *.raw to *.hkl)
(Apply absorption correction if needed.)
(produces name.HKL file and printable output)

[BACKUP DATA TO CD-R]
(Smartuse account using bakcd.)






STRUCTURE SOLUTION AND REFINEMENT

(Back to top of map.)

[MAKE USER ACCOUNT]
(One per structure.)

[TRANSFER DATA]
(From smartuse or apexuser account to user account.)

RENAME DATA FILE (*.hkl) TO F2.DAT

START TEXSAN
(Enter needed data about cell and contents.)

PROCESS
(converts f2.dat --> hkl.dat)
(Printed output of results.)
(Check output for correct space group assignment.)

HKL (p-factor)
(Apply p-factor to data)
(modifies hkl.dat)

HKL (Average)
(Average equivalent and redundant data)
(old hkl.dat --> hkl.save)

SOLVE
(SIR97 -- usually)

MODEL
GRAPHICS EDIT
(Assign atom names to peaks)

EXPAND SOLUTION
(If necessary -- i.e., lots of missing atoms)
(If not, then go straight to Isotropic Refinement.)


* ISOTROPIC REFINEMENT
LSQ plus FOUR

(Refine atoms, run difference Fourier.)
(Print LSQ output, sometimes FOUR output)

ASSIGN NEW ATOMS
(Assign atom names to significant peaks.)

[Got all atoms? No -- go  back to ISOTROPIC REFINEMENT. Yes -- continue.]

ANISOTROPIC REFINEMENT
(Convert heavy atoms first, then lighter.)

** LSQ plus FOUR
(Print LSQ output)

(Repeat until all atoms anisotropic and refinement converged.)

LOOK FOR HYDROGENS
(Look in difference Fourier map.)

[Can we see them in the map?]
[Yes. - Continue. No. - Consider stopping]

PREDICT HYDROGEN POSITIONS
(GEOMETRY in GRAPHICS EDIT)

(Repeat from ** checking the difference Fourier until converged.)

INSPECT DATA
(Look for "bad" data.)
(Look for secondary extinction.)
(Apply needed corrections. Continue from ** until converged)

FINAL REFINEMENT
(Include "unobserved" data.)

SET UP TABLES

SET UP REPORT

MAKE PRETTY PICTURES WITH ORTEP.

WRITE UP AND [CHECKOUT].