Index

Core dictionary version 3.0.14

_refln.form_factor_table

Definition:

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

Type: Real

Values appear in Table context.

Dimension: []

Units: none

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 ) {
 
            c  =   t.Cromer_Mann_coeffs
 
            f  =  (c[0] + c[1] * Exp (-c[2] * s*s)
                        + c[3] * Exp (-c[4] * s*s)
                        + c[5] * Exp (-c[6] * s*s)
                        + c[7] * Exp (-c[8] * s*s))
       } Else {
 
            c  =   t.hi_ang_Fox_coeffs
 
            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