$STONE

$STONE group (optional)

This group defines the expansion points for Stone's distributed multipole analysis (DMA) of the electrostatic potential.

The DMA takes the multipolar expansion of each overlap charge density defined by two gaussian primitives, and translates it from the center of charge of the overlap density to the nearest expansion point. Some references for the method are

Stone, Chem.Phys.Lett. 83, 233 (1981)
Price and Stone, Chem.Phys.Lett. 98, 419 (1983)
Buckingham and Fowler, J.Chem.Phys. 79, 6426 (1983)
Stone and Alderton, Mol.Phys. 56, 1047 (1985)

The existence of a $STONE group in the input is what triggers the analysis. Enter as many lines as you wish, in any order, terminated by a $END record.


ATOM i name, where
ATOM is a keyword indicating that a particular atom is selected as an expansion center.

i is the number of the atom

name is an optional name for the atom. If not entered the name will be set to the name used in the $DATA input.


ATOMS
is a keyword selecting all nuclei in the molecule as expansion points. No other input on the line is necessary.

BOND i j name, where
BOND is a keyword indicating that a bond mid- point is selected as an expansion center.

i,j are the indices of the atoms defining the bond, corresponding to two atoms in $DATA.

name an optional name for the bond midpoint. If omitted, it is set to 'BOND'.


CMASS
is a keyword selecting the center of mass as an expansion point. No other input on the line is necessary.

POINT x y z name, where
POINT is a keyword indicating that an arbitrary point is selected as an expansion point.

x,y,z are the coordinates of the point, in Bohr.

name is an optional name for the expansion point. If omitted, it is set to 'POINT'.


The second and third moments on the printout can be converted to Buckingham's tensors by formula 9 of
A.D.Buckingham, Quart.Rev. 13, 183-214 (1959)
These can in turn be converted to spherical tensors by the formulae in the appendix of
S.L.Price, et al. Mol.Phys. 52, 987-1001 (1984)


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