Our first observation is that, for each molecule-space group combination, the QR search and the three repeats of QR-BH all find the same global energy minimum structure. Therefore, we are confident that the true global energy minimum has been located for each system. The efficiency of the methods is measured by the number of steps required to locate the global minimum of each system (Table ). This is defined straightforwardly in the QR search as the number of accepted (lattice energy minimized) quasi-random seeds until the first time that the global minimum is located. For the QR-BH search, we define the step as the product of (seed number)×(BH step number) for the first hit to the global minimum.