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+ | ====== s ====== | ||
+ | |||
+ | **[// | ||
+ | |||
+ | The Rietveld scale factor, can be applied to all phase types . | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Used for applying intensity corrections to phase peaks. The following example defines a Lorentz-Polarisation correction: | ||
+ | |||
+ | scale_pks = (1+Cos(c Deg)^2 Cos(2 Th)^2)%%/ | ||
+ | |||
+ | // | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Initialises the random number generator with a seed based on the computer clock. | ||
+ | |||
+ | **[//site// $site [//x// E] [//y// E] [//z// E] ]...** | ||
+ | |||
+ | **[//occ// $atom E [//beq// E]]...** | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Defines a site where $site is a User defined string used to identify the site. | ||
+ | |||
+ | //x//, //y//, and //z// defines the fractional atomic coordinates, | ||
+ | |||
+ | //occ// and //beq// defines the site occupancy factor and the equivalent isotropic temperature factor beq. $atom corresponds to a valid atom symbol or isotope the data of which is contained in the file ATMSCAT.CPP for x-ray data and NEUTSCAT.CPP for // | ||
+ | |||
+ | // | ||
+ | |||
+ | //inter// corresponds to the sum of all GRS interactions which are a function of the //site//. The value of //inter// can represent the site electrostatic potential depending on the type of GRS interactions defined. | ||
+ | |||
+ | Definition of a site fully occupied by aluminium: | ||
+ | |||
+ | site Al1 x 0 y 0 z 0.3521 occ Al+3 1 beq 0.3 | ||
+ | |||
+ | Definition of a site occupied by two cations: | ||
+ | |||
+ | site Fe2 x 0.9283 y 0.25 z 0.9533 occ Fe+3 0.5 beq 0.25 | ||
+ | |||
+ | occ Al+3 0.5 beq 0.25 | ||
+ | |||
+ | **[// | ||
+ | |||
+ | **[// | ||
+ | |||
+ | When used in equations the name N of // | ||
+ | |||
+ | N of // | ||
+ | |||
+ | < | ||
+ | |||
+ | where tol corresponds to // | ||
+ | |||
+ | #eq, #n1, #n2 and #n3 correspond to the site equivalent position and fractional offsets to add to the sites. This is useful if the structure is already known and constraints are required, for example, in the bond length output (see // | ||
+ | |||
+ | Zr1:0 O1:20 0 0 -1 2.08772 | ||
+ | |||
+ | O1:7 0 -1 0 2.08772 89.658 | ||
+ | |||
+ | O1:10 0 0 -1 2.08772 90.342 90.342 | ||
+ | |||
+ | O1:15 -1 0 0 2.08772 180.000 89.658 89.658 | ||
+ | |||
+ | O1:18 -1 0 0 2.08772 90.342 89.658 180.000 90.342 | ||
+ | |||
+ | |||
+ | |||
+ | P1:0 O1:4 0 0 0 1.52473 | ||
+ | |||
+ | O1:8 0 0 0 1.52473 112.923 | ||
+ | |||
+ | O1:0 0 0 0 1.52473 112.923 112.923 | ||
+ | |||
+ | O2:0 0 0 0 1.59001 105.749 105.749 105.749 | ||
+ | |||
+ | Example constraints using macros could look like the following: | ||
+ | |||
+ | Angle_Restrain(O1 P1 O1 8, 112, 112.92311, 0, 0.001) | ||
+ | |||
+ | Angle_Restrain(O1 18 -1 0 0 Zr1 O1 10 0 0 -1, 89, 89.65750, 0, 0.001) | ||
+ | |||
+ | Distance_Restrain(Zr1 O1 20 0 0 -1, 2.08, 2.08772, 0, 1) | ||
+ | |||
+ | BENZENE.INP demonstrates the use of the restraint macros Distance_Restrain, | ||
+ | |||
+ | **[// | ||
+ | |||
+ | **[// | ||
+ | |||
+ | // | ||
+ | |||
+ | sites_geometry some_name | ||
+ | |||
+ | load site_to_restrain { C1 C2 C3 C4 } | ||
+ | |||
+ | Three functions, Sites_Geometry_Distance($Name), | ||
+ | |||
+ | If $Name contains only two sites then only Sites_Geometry_Distance($Name) can be used. Three sites defined additionally allows the use of Sites_Geometry_Angle($Name) and four sites defined additionally allows the use of Sites_Geometry_Dihedral_Angle($Name). | ||
+ | |||
+ | Examples SITES_GEOMETRY_1.INP and SITES_GEOMETRY_2.INP demonstartes the use of // | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Defines the S< | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Performs a Savitzky-Golay smoothing on the observed data. The smoothing encompasses (2 * # | ||
+ | |||
+ | **[// | ||
+ | |||
+ | **[// | ||
+ | |||
+ | **[// | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Defines a hkl dependent symmetrized spherical harmonics series (see section 7.9.2). $name defines the name given to the series and when used in equations it returns the value of the spherical harmonics series. | ||
+ | |||
+ | // | ||
+ | |||
+ | // | ||
+ | |||
+ | // | ||
+ | |||
+ | The PO_Spherical_Harmonics macro simplifies the use of // | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Defines hat sizes for generating an aberration function comprising a summation of hat functions. // | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Defines the start and finish X region to fit to. | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Defines a new structure node. | ||
+ | |||
+ | **[// | ||
+ | |||
+ | Defines a parameter name and a vector normal to the plane defined by h, k and l. When the parameter name is used in an equation, it returns angles (in radians) between itself and the normal to the planes defined by hkls; see the Preferred_Orientation and PO_Two_Directions macros. An example in two directions is as follows: | ||
+ | |||
+ | **[****// | ||
+ | |||
+ | // | ||
+ | |||
+ | While // | ||
+ | |||
+ | k = 0 | ||
+ | |||
+ | Do | ||
+ | |||
+ | Randomize the cation configuration according to // | ||
+ | |||
+ | Find the local minimum of < | ||
+ | |||
+ | k = k + 1 | ||
+ | |||
+ | If < | ||
+ | |||
+ | While < | ||
+ | |||
+ | } | ||
+ | |||
+ | Starting from a particular cation configuration, | ||
+ | |||
+ | Swapping the Zr sites with and Ca sites in the example above can be performed as follows: | ||
+ | |||
+ | swap_sites Ca Zr | ||
+ | |||
+ | If the sites were named Ca1, Ca2, Ca3, Zr1, Zr2, Zr3 then the following could be used: | ||
+ | |||
+ | swap_sites Ca* Zr* | ||