Patterson Map Calculation with Program XPREP

1. Copy the Denzo/Scalepack output file output.sca into your working directory.

2. From that working directory, type "xprep" to start the XPREP program.

3. XPREP program will is very instructive and will give several choices at each step. User should just follow instruction to select option from the list. Following is the procedure to run XPREP with output.sca (space group I4).

4. Input filename for the XPREP program:

1) Filename: output.sca
2) Select Option [D]: D or return [D] Denzo/Scalepack .sca file
3) Use cell from Denzo/Scalepack [Y]: Y or return
4) Select Option [I]: I or return [I] Lattice type I

5. Determine or input space group (from main menu):

1) Select Option [S]: S or return [S] Determine or input space group
2) Select Option [I]: I or return [I] Input known space group
3) Enter symbol: I4
4) From the menu, user may use the program to determine the space group if unknown.

6. Absorption, powder, SIR, SAD, MAD (from main menu)

1) Select Option [H]: A [A] Absorption,powder,SIR,SAD,MAD
2) Select Option [S]: A [A] MAD, SAS, SIR or SIRAS
3) Select Option [E]: A [A] SAS
4) High resolution limit in A for this calculation: 3.5
5) I/Sigma threshold for rejecting [0.5]: return
6) Target number of reflection in local scaling sphere [100]: return
7) High resolution limit in A for saved data: return
8) Enter effective B-value to normalize delta-F or Fa values: return (for no)
9) Filename to write FA and phi(T)-phi(A): test
10) Select Option [S]: E [E] Exit to main menu

7. Calculate Patterson map (from main menu):

1) Select Option [H]: P [P] Contour Patterson section
2) Follow the instructions to select harker section to contour the Patterson map.

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