The process begins with a trial molecular structure. "You essentially toss the atoms into a shoebox," says Miller, "with enough knowledge to make sure the structure makes chemical sense." The computer calculates a set of phases corresponding to these atomic positions and then randomly perturbs them, the shake part of the process, to arrive at a lower value in accord with Hauptman's formula. Then a new set of atomic positions is calculated, and the method continues, back and forth between atomic positions and phases as many as 200 times for a single trial structure. When enough trial structures have been shaked and baked, the right answer will emerge as a significantly low value for Hauptman's formula, at least that is the theory, and so far the researchers are, in Hauptman's words, "very much encouraged."
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