**Hydropathic Term***enumerated choices: {Off|exp(-nr)|(1/r**n)}*- The Hydropathic Term of the Distance Function controls
the mathematical form of the distance dependence for
hydropathic interactions. (See Theory Chapter for more
information.) Off disables the hydropathic term; exp(-nr)
uses an exponential decay function to represent the
distance dependence of hydropathy through space; (1/r**n)
uses an inverse power function to represent the distance
dependence of hydropathy through space. The value of n
is set in a separate parameter.
**n***integer number*- The n parameter is the integer number in the (1/r**n)
hydropathic term of the HINT distance function.
**Steric Term***on/off*- The Steric_Term of the Distance_Function is an adaptation
of the Lennard-Jones function. For the most part it
represents a penalty function to prevent the too-close
approach of interacting atoms. In general, use the
Steric_Term for Map and HintTable interaction calculations,
but don't use it for Molecule and Complement Map
calculations.
**Steric/Hydro Scaler***real number*- The Steric/Hydro Scaler is an empirical parameter designed
to balance the two terms (Steric and Hydropathic) of the HINT
Distance_Function. Experience has shown that a value of 50.0
for this parameter gives a HINT atom-atom interaction score
that is about 2/3 hydropathic and 1/3 steric for an acid-base
interaction at Van der Waals contact distance. The primary
purpose, however, of the HINT Steric_Term is to flag invalid
contact distances between interacting atoms.
**Direction Vectors***enumerated choices: {None (Spherical)|Bond Axes (Geom.)|Hybridizd/Lone Pair}*- The Direction Vectors parameter(s) provide a mechanism
to more specifically direct hydropathy along either Bond
Axis or Lone Pair vectors. This is especially important
for polar/H-Bond interactions where directionality of
interactions is expected to be important. Hydrophobic
interactions are less likely to be directional.
- Bond Axes (Geom.) directs the hydropathy along the
axis of the bond (or average of bonds) to the selected
atom.
- Hybridizd/Lone Pair directs the hydropathy along
vectors coinciding with the placement of lone pairs
and pi orbitals on the selected atom. The magnitude
of these vectors are weighted for the occupancy (lectrons)
of the lone pair or pi orbital.
**Vector Focus***real number*- The Vector Focus parameter allows control over the
focus of the directionality vectors, larger Vector
Focus parameters cause a tighter focus of the probability
function controlling interactions.