X-Ray crystal structure Refinement The model ∴:: The data: Actual 一+:: intensities of sp0 intensities of spots ● xm=∑[k- h k/ Summation Actual intensity of spot Intensity of spot calculated runs over spots observed in expt from trial structure U Molec model SUx ay expt Simulated annealing on hybrid potential rapidly improves correspondence between structure and X-ray observations while maintaining reasonable chemistry (large radius of convergence Previous method effectively used local minimization which became trapped in local minima(small radius of convergenceX-Ray Crystal Structure Refinement The model: Computed The data: Actual intensities of spots intensities of spots Fobs ( h,k,l) − Fcalc ( h,k,l) ] 2 UX -ray expt = ∑ [ Summation h ,k ,l Actual intensity of spot Intensity of spot calculated runs over spots observed in expt from trial structure Uhybrid = U Molec Model + sU expt ray -X • Simulated annealing on hybrid potential rapidly improves correspondence between structure and X-ray observations while maintaining reasonable chemistry (large radius of convergence) • Previous method effectively used local minimization which became trapped in local minima (small radius of convergence)