HO-MM-1 homonuclear molecular mechanics interface
Summary:
The HO-MM-1 interface is used for potential energy subprograms capable of
handling an arbitrary number of identical atoms. The driver program passes the
geometry as a set of cartesian coordinates for each atom, and the potential energy
and first derivatives are returned.
Format and selected details:
In general, a HO-MM-1 potential energy routine has the following format:
SUBROUTINE POT( X, Y, Z, E, DEDX, DEDY, DEDZ, NATOM, MAXATOM)
DIMENSION X(MAXATOM), Y(MAXATOM), Z(MAXATOM)
DIMENSION DEDX(MAXATOM), DEDY(MAXATOM), DEDZ(MAXATOM)
E = SOME FUNCTION OF ( X, Y, and Z )
DEDX = SOME FUNCTION OF ( X, Y, and Z )
DEDY = SOME FUNCTION OF ( X, Y, and Z )
DEDZ = SOME FUNCTION OF ( X, Y, and Z )
RETURN
END
Required variables:
The subroutine POT takes the following arguments
POT ( X(NATOM), Y(NATOM), Z(NATOM), E, DEDX(NATOM), DEDY(NATOM), DEDZ(NATOM), NATOM, MAXATOM )
where
| NATOM |
input, integer |
The number of identical atoms.
|
| MAXATOM |
input, integer |
Sets the dimension of the cartesian variables
X, Y, and Z. MAXATOM must be greater than or equal
to NATOM.
|
X(NATOM)
Y(NATOM)
Z(NATOM) |
input, double precision |
One-dimensional arrays containing the X, Y, and Z
components of all NATOM atoms, where the index labels
the atoms.
|
| E |
output, double precision |
The potential energy.
|
DEDX(NATOM)
DEDY(NATOM)
DEDZ(NATOM) |
output, double precision |
One-dimensional arrays containing the first derivatives
of the energy E with respect to the X, Y, and Z components
of all NATOM atoms, where the index labels the atoms.
|