xray <xray-statement> end
<xray-statement> :==
reset
Erases xray database.
symmetry=?|reset|<symmetry-operator>
Add a symmetry operator to symmetry database.
Operators are from the International tables e.g. (-x,y+1/2,-z)
and must include parenthesis. Reset removes all operators
except identity.
scatter <atom-selection> <real> <real> <real> <real> <real>
<real> <real> <real> <real> [fp <real>] [fdp <real>]
Scattering factor parameters a1, b1, a2, b2, a3, b3, a4, b4, c, i
The atomic form factor for selected atoms is:
f(real)=sum(i=1,4) a[i] exp(-b[i] s**2/4) + c + f' + if''
scatter ?
Print info about current atomic form factors.
associate <xray-object> <atom-selection>
Associate a reciprocal space object with the specified atoms.
Default: associate fcalc ( not hydrogen ).
Multiple associate statements are permitted.
method=direct|fft
Use direct summation or fast Fourier transform. Default=fft
tolerance=<real>
Tolerance (in Angstroms) for recalculating structure factors used
in target calculation. If tolerance is exceeded, structure factors
are re-calculated during calls to energy.
Recommended: 0.0 for minimization and 0.2 for dynamics.
wa=<real>
Overall weight for target function.
flip
Flip all friedel mates.
generate <real> <real>
Generate additional reflections to produce a full asymmetric unit
of reflections for the specified resolution range.
expand
Expand all reflections and symmetry operations to P1.
unexpand
Un-does the expand statement. This is only possible if
reflections and/or symmetry operations were not altered since
the last expand statement.
bins=<integer>
Number of reciprocal space bins. Default=8
Declares a symbol $bin_number.
binresolution <real> <real>
Resolution limits of reciprocal space binning.
declares symbols $bin_resolution_low and $bin_resolution_high.
print target
Print the current value of the crystallographic target.
Also defines symbols: $target, $test_target, $monitor and $test_monitor.