HELENA

PLATON HOMEPAGE

WHAT IS HELENA?

CAD4-DATA are assumed to be in a file named: 'helena.cad' (including psi-scan data when applicable).

(An example CAD4-file, collected on a TurboCAD4/Rotating Anode for the CAD4 test crystal (= ammonium hydrogen tartrate) is included)

HELENA can be invoked in 'S' via clicking on the appropriate menu button

or directly via

platon -k

The normal input to the program on the '>>' prompt is (Depending on the local hardware setup, i.e. beta filter or monochromator):

• MONOCHR BETA (for Beta Filter) or
• MONOCHR PAR (for sealed tube CAD4 or
• MONOCHR PERP (for rotating Anode setup)

followed by clicking on

CALC-SHELX

and (repeated) clicking on

NEXT-STEP

As a result, the program will generate a SHELX(L).HKL file (HKLF 4 - format) suitable for use with SHELX, SHELXS and SHELXL. (with direction cosines suitable for absorption correction with PLATON)

Psi-scan data follow regular reflections on shelx.hkl separated by a blank line (i.e. E.O.F. mark for SHELX(S/L)

Note:

1. The applicable filterfactor should be provided in the last number in record #32 in the CAD4-file (after the two lambda's).

2. There can be no garantie that it also works in other SET-UPs. The program is updated regularly.

3. An analyses of 'shelxl.hkl' data for the applicable space group may be attempted with the program PLATON:

   what will be needed is a file 'shelx.ins' containing:

         TITLE text 
         CELL lambda a b c alf bet gam
         SPGR   (blank)
   

   Invoke: platon shelx.ins

   However this analysis is only tentative, the ultimate decision is to the user.

HELENA Instructions

1. CALC-SHELX
3. ScaleDegree
5. LIST-REFL
6. N0-SCALE
7. BetaPerpPar
8. LSR-MSM-MSA
9. DirCos-ABSP
11. Include RR1
12. Include RR2
13. Include RR3
14. Include RR4
15. Include RR5
16. Include RR6
17. Include RR7
18. Include RR8
19. Include RR9
25. NEXT-STEP