Index

Core dictionary version 3.3.0

_refln.form_factor_table

Definition:

   
    Atomic scattering factor table for the scattering angle
    of this diffraction vector and atom types in the structure.

Type: Real

Values appear in Table context.

Definition method:

         _units.code = "none"

         If (_diffrn_radiation.probe == "neutron")
             _units.code = "femtometres"

Evaluation method:

         With r  as  refln

           table = Table ()
           s  =    r.sin_theta_over_lambda

           Loop t  as  atom_type  {

             If (_diffrn_radiation.probe == 'neutron') {

               f  =   t.length_neutron

             } Else If (s < 2.0 ) {

               cmc  =   t.Cromer_Mann_c
               cma  =   t.Cromer_Mann_as
               cmb  =   t.Cromer_Mann_bs

               f  =  (cmc + cma[0] * Exp (-cmb[0] * s*s)
                          + cma[1] * Exp (-cmb[1] * s*s)
                          + cma[2] * Exp (-cmb[2] * s*s)
                          + cma[3] * Exp (-cmb[3] * s*s))
             } Else {

               c  =   t.hi_ang_Fox_coefs

               f  =   Exp ( c[0] + c[1]*s + c[2]*s*s + c[3]*s*s*s )
             }

             table [ t.symbol ]  =   f

           }
         _refln.form_factor_table  =   table

Category:
refln