With respect to the first reply: I have observed minimization failures from structures in which the “before energy” was as low as 1408. (Less than 1/2000 of the randomized structures possess energies less than 2000).
With respect to the second reply: the before, and after structures from failed minimizations usually (it could be always) have one domain interpenetrating the other. (I had originally hoped to use minimization to eliminate the interpenetration and leave the domains in contact. Now I realize that I’d need to restrict attention to those randomized structures in which any domain interpenetration distance is less than an atomic radius, which I’d hope would merely be those structures in which the energy is less than some value. The minimization failure mentioned in the previous paragraph suggests that this may not work however.
If the minimization function becomes confused, shouldn’t it at least return the same energy and structure as it was first given?