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Use of negative quartet cosine invariants as a phasing figure of merit: NQEST

96

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References

1975

Year

Abstract

Recent theoretical advances in the identification of those cosine invariants cos (ϕh + ϕk + ϕ1 + ϕm) which are probably negative suggest algorithms for the calculation of a figure of merit which is sensitive to the integrity of a phase set. The negative quartet figure of merit, NQEST, defined here is of particular utility in conjunction with fast multi-solution tangent formula techniques. Development of the methods and applications to both known and unknown crystal structures are presented.