Data items in the PHASING_MIR_DER_REFLN category record details
about the calculated structure factors obtained in an MIR
phasing experiment.
This list may contain information from a number of different
derivatives; _phasing_MIR_der_refln.der_id indicates to which
derivative a given record corresponds. (A derivative in this
context does not necessarily equate with a data set; see the
definition of the PHASING_MIR_DER category for a
discussion of the meaning of derivative.)
It is not necessary for the data items describing the measured
value of F to appear in this list, as they will be
given in the PHASING_SET_REFLN category. However, these
items can also be listed here for completeness.