SIR92 Normal

Preparation of data for NORMAL routine


NREF n

Number of reflections with largest E-values subject to a minimum value of E(obs) = 1.2.

           Default = 4 * number of independent atoms
                         + 50 if centrosymmetric
                         + 50 if triclinic + 150
to a maximum of 499. If PSEUDO directive is on, the program tries to use all the E's down to 1.2.

NZRO n

Number of smallest E-values to calculate psi(zero) triplets. Default is 1/3 of strong reflections.

BFAC x

Temperature factor if the user wants to supply it.

PSEUDO n(1,1) n(2,1) n(3,1) n(4,1) n(1,2) . . . n(4,3)

If parameters are equal to zero, or omitted, the normalization routine performs statistics for the pseudotranslation effects and renormalizes the reflections on assuming the most probable pseudotranslation as prior information. If user wants to supply a specific pseudotranslational symmetry, and this corresponds to a class given in Table 1 the n(1,1) can be set to the class number and the other values must be omitted. If the pseudotranslation is more complex, it should be specified by up to 3 sets of 4 values n(i,j) so that

               ( n(1,j)*h + n(2,j)*k +n(3,j)*l =n(4,j)*m )   j=1,3

where m is an integer number.

PARTIAL

To perform the procedure which aims at recovering the complete structure from a partial one. This instruction is followed by the list of atomic information (one per card) consisting of atomic type, x, y, z and optionally occupancy factor (default 1.0). See Example 3 - 4. Please consider the directive FRAGMENT in module FOURIER/LEAST-SQUARES for a different approach.