The Read Best Conformations degree of freedom reads a conformation file (CG file) produced by another run of the CONGEN command, and selects the best conformations from it. Each conformation selected is considered one sampling for this degree of freedom. It is potentially useful when a complete search would take too long to complete. In such a case, a search over part of the atoms would be written out, and then a low energy subset would be read back for use.
The UNIT option specifies the Fortran file unit where the input conformation file is read. NBEST specifies how many conformations are read back in the following way: The file is first scanned and the energy of each conformation is recorded in an array. The array is sorted and then, the NBESTth lowest energy is selected. During the actual sampling process, the conformation file is scanned again, and any conformation having an energy less than or equal to the selected energy is used. Thus, if several conformations have the same energy, it is possible for more than NBEST conformations to be read in.
MAXEVDW specifies the maximum van der Waals repulsion for any atom read by this degree of freedom. If the parameter file specifies that hydrogen bonds should exclude the non-bonded energy, see Parameter File Format, then the hydrogen bond potential will be used to calculate the distance corresponding to MAXEVDW for interactions involving hydrogen bondable atoms.