Data Item _phasing_MIR_der_refln.HL_D_iso


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The isomorphous Hendrickson-Lattman coefficient Diso for this reflection for this derivative. -2.0 * Fpobs2 * sin(alphahcalc)2 * cos(alphahcalc)2 Diso = ---------------------------------------- E2 E = (Fphobs - Fpobs - Fhcalc)2 for centric reflections = [(Fphobs - Fpobs) * 21/2 - Fhcalc]2 for acentric reflections Fpobs = the observed structure-factor amplitude of the native Fphobs = the observed structure-factor amplitude of the derivative Fhcalc = the calculated structure-factor amplitude from the heavy-atom model alphahcalc = the phase calculated from the heavy-atom model This coefficient appears in the expression for the phase probability of each isomorphous derivative: Pi(alpha) = exp[k + A * cos(alpha) + B * sin(alpha) + C * cos(2 * alpha) + D * sin(2 * alpha)] Ref: Hendrickson, W. A. & Lattman, E. E. (1970). Acta Cryst. B26, 136-143.

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