3.66. STARTX: Create initial archive file
| label | descriptive information |
| cell | unit cell parameters |
| cellsd | standard deviations in unit cell parameters |
| sgname [a] | space group name in explicit-origin Hall notation |
| spaceg | space group name in Hermann-Maugin notation |
| latice [a] | unit cell lattice type and centricity |
| symtry [a] | symmetry equivalent positions |
| celmol | number of molecules in the cell |
| celcon | contents of unit cell atomic species information |
| formfx [b] | scattering factor information, tabular |
| formgn [b] | scattering factor information, expansion coefficients |
| scale [c] | Frel scale factors for data sets |
| maxhkl [c] | maximum sin / , h, k, and l for datasets |
| datdef [c] | definition of crystal data set (enantiomorph, etc.) |
| exper [c] | experimental conditions for data sets |
| crystal | crystal colour and dimensions |
| orient [c] | crystal orientation for data sets |
| Notes: a. Symmetry information must be entered by using either a sgname line or a latice line and/or one or more symtry lines. b. CELCON lines must precede these lines. For a given atom type, both formfx and a formgn lines may not be used. However, a formfx line for atom type 1 and a formgn line for atom type 2 may be used. If neither is entered, stored expansion coefficients will be used by default for atoms specified on the CELCON lines (Cromer and Mann, 1968). c. These lines, if entered, must follow the CELCON lines. | |
| STARTX | Option | Code | Arg | Def | |
| bdf creation | apr | create an a priori output archive bdf | |||
| upd | output updated from input bdf | ||||
| stored form factors | sint | s | sin/ interpolation int. | 0.02 | |
| smax | s | sin/ maximum | 2.0 | ||
| radiation type | xray | X-rays | |||
| neut | neutrons | ||||
| elec | electrons | ||||
| lax | no symmetry checking at all |
| label | 1 | character information added to the logical record lrlabl: of the bdf |
| sgname | 1- | space group in Hall notation [a] | |
| Notes: a. A table of these notations, together with the corresponding space group as found in the International Tables, Vol. A., is located in the Symmetry appendix. (NOTE that separate elements of the notation must be separated by space or underscore characters e.g. p_2_2 not p22. ) | |||
| spaceg | 1- | space group in Hermann-Maugin notation [a] | |
| Notes: a. Separate elements of the notation must be separated by space or underscore characters e.g. P 1 21 2 not P1211. Note also that because colons (:) denote specific settings they cannot be used as XTAL comment delimiters on spaceg lines. | |||
| latice [a] | 1 | centricity code | |||
| centrosymmetric | c | ||||
| noncentrosymmetric | n | ||||
| 2 | Bravais lattice code | ||||
| primitive | p | ||||
| end-centred | a , b , c | ||||
| body-centred | i | ||||
| rhombohedral | r | ||||
| face-centred | f | ||||
| 3 | no symmetry checks [b] | ncheck | |||
| Notes: a. If this line is entered then the equivalent positions described by the centricity and Bravais lattice codes must not be input as symtry lines. This line must NOT be entered if an sgname line is used. b. no symmetry checks will be applied to input symtry lines and the sgname code will not be automatically generated and stored. This option is invoked if special symmetry is to be entered. | |||||
| symtry [a] | 1- | equivalent positions entered as algebraic strings | |
| Notes: a. Symmetry equivalent positions are entered as listed in the International Tables, Vol I or A. If the latice line is entered then the equivalent positions described by the centricity and Bravais lattice codes must not be input as symtry lines. The definition of an equivalent position is the x, y, and z operations for each coordinate separated by commas. Only one equivalent position may be defined on a symtry line. This line must NOT be entered if an sgname line is used. Xtal comments (preceded by a colon :) are not permitted. | |||
| celcon [a] | 1 | atom type symbol (max 8 characters) | |
| 2 | number of atoms of this type in the unit cell | ||
| 3 | atomic weight | based on field 1 | |
| 4 | atomic number | based on field 1 | |
| 5 | number of electrons in atom type | based on field 1 | |
| 6 | atomic bond radius (in Å) | based on field 1 | |
| 7 | atomic contact radius (in Å) | based on field 1 | |
| 8 | real dispersion factor f' [b] | based on field 1 | |
| 9 | imaginary dispersion factor f" [b] | based on field 1 | |
| 10 | neutron scattering factor (CAUTION [c]) [d] | based on field 1 | |
| Notes: a. One celcon line must be entered for each atom type expected in the structure. If neither formgn nor formfx lines are used, scattering factors will be generated using information on celcon lines and tables from Cromer and Mann (1968). b. The dispersion factors are automatically entered only for MoK and CuK  1 radiations.
Actually, as of Xtal-3.7.2 dispersion factors in the wavelength range
0.1Å to 2.89Å can be automatically added based on the
calculations of S. Sasaki (1989) KEK report, which you should acknowledge.
The radiation wavelength is specified on the
exper line.c. If the neutron scattering factor is entered, ALL subsequent calculations will require that neutron data be processed. Do not enter unless this is the case. d. If the command STARTX neut is invoked then the neutron scattering length is automatically added to the archive. | |||
| formfx [a] | 1 | atom type symbol (max 8 characters) | |
| 2 | sin/ for scattering factor | ||
| 3 | scattering factor value | ||
| 4 | comment about source of scattering factor (surround with '=') | ||
| Notes: a. Not more than 200 formfx lines are allowed per atom type. Lines must be in order of increasing sin /. The first line must
have a sin/ value of zero. | |||
| formgn [a] | 1 | atom type symbol (max 8 characters) | |
| 2-10 | Cromer-Mann coefficients a1, b1, a2, b2 , a3, b3, a4, b4, c | ||
| Notes: a. One formgn line is used per atom type. | |||
| scale | 1 | Frel scale | |
| 2 | scale group number | 1 | |
| 3 | data set number | 1 | |
| 4-6 | same as fields 1-3 for next scale; and so on |
| maxhkl | 1-3 | max |h|, |k|, |l| to be stored on the bdf | |
| 4-5 | min and max sin/ to be stored on the bdf | ||
| 6 | data set number | 1 |
| exper | 1 | data set number | 1 |
| 2 | weighted mean wavelength (in Å) | 0.71069 (X rays) | |
| 1.0 (neutrons) | |||
| 0.01 (electrons) | |||
| 3 | wavelength line 1 | ||
| 4 | wavelength line 2 | ||
| 5 | wavelength line 3 | ||
| 6 | relative weight line 1 | ||
| 7 | relative weight line 2 | ||
| 8 | relative weight line 3 | ||
| 9 | measured density of crystal (mg/mm3) | ||
| 10 | linear absorption coefficient | ||
| 11 | temperature of measurement (in Celsius) | ||
| 12 | sorting order for hkl as packed integer e.g.213 is k-slow, l-fast | ||
| 13 | pressure of measurement (in GPa) | ||
| 14 | radiation type (1=neutron 2=electron 3=MoKa 4=CuKa 5=AgKa 6=synch) | ||
