Input Data Blocks Needed by UFF

$coord

cartesian coordinates of the atoms (default: $coord file=coord)

$ufftopology

contains a list of the next neigbours of each atom (see Section 15.2.4). Sometimes it is useful to enter the connectivity (in the input block nxtnei12 in the file ufftopology) by hand (not always necessary; default: $ufftopology file=ufftopology).

Beyond this uff reads the force field parameters for the atoms from the file parms.in. If this file exists in the directory from which one starts an uff calculation the program will use this file, if not the program reads the data from the file $TURBODIR/uff/parms.in. If one wants own atom types, one has to add these atoms types in the file parms.in. For each new atom type one has to specify the natural bond distance, the natural bond angle, the natural non-bond distance, the well depth of the Lennard-Jones potential, the scaling factor ζ, the effective charge, torsional barriers invoking a pair of sp³ atoms, torsional barriers involving a pair of sp² atoms, generalized Mulliken-Pauling electronegativities, the idem potentials, characteristic atomic size, lower bound of the partial charge, upper bound of the partial charge. Distances, energies and charges are in atomic units and angles are in rad.