Chemical Crystallography

+ Frequently Asked Questions

- Crystals Primer

1. Getting Started

2. Example Of A Simple Structure

3. Overview

4. Basic Data Input

5. The Model

6. Fourier Maps

7. Preparation Of The Model

8. Refinement

9. Seeing The Structure

10. Molecular Geometry

11. Publication Listings

12. Cif Files

13. Documentation

14. The Data Base

15. Tailoring The Program

16. Advanced Refinements

17. Scripts

18. Data Lists And Instructions

+ Crystals User Guide

+ Crystals Manual

+ Cameron Manual

+ Index

Fri Jun 2 2000
   

Crystals Primer

Chapter 4: Basic Data Input

4.1: Start up


CRYSTALS has powerful reflection processing features, described in the Reference Manual. A simplified input is available if the user knows the unit cell, space group, molecular formula and has a file (e.g. REFLECTIONS.DAT) containing reflections in the form h, k, l, Fsq, Sigma(Fsq), one per line.
 

4.1: Start up

      !\QUICKSTART
      !CELL         4.05 11.74 24.80
      !SPACEGROUP   P b c n
      !CONTENT      C 13 H 8 O I 2
      !DATA         1.5418       I
      !FILE         CRDIR:REFLECTIONS.DAT
      !FORMAT       (3F4, 2X, 2F8.2)
      !END
      !\LIST 28
      !MINIMA       RATIO=2.5
      !END

 

 
\QUICKSTART
 
\SCRIPT QUICKST

Use QUICKSTART for normal situations. This command requires minimal user input, and sets up the basic data lists in the data base. See the manual for a description of the lists created, and how to deal with complicated cases. Permitted reflection data types are Fo, Fsquare, and I. The Lp correction for 4 circle geometry is applied if the type is I. LIST 28 sets the minimum value of I/sigma(I) to be used in calculations.
 
\SCRIPT CADQUICK
 
\SCRIPT CADSLOW

These SCRIPTS takes as input the files produced by the CAD4 data processing program RC93 (or RC85).