$SURF

$SURF group (relevant for RUNTYP=SURFACE)

This group allows you to probe a potential energy surface along a small grid of points. Note that there is no option to vary angles, only distances. The scan can be made for any SCFTYP, or for the MP2 or CI surface.

IVEC1
= an array of two atoms, defining a coordinate from from the first atom given to the second.

IGRP1
= an array specifying a group of atoms, which must include the second atom given in IVEC1. The entire group will be translated (rigidly) along the vector IVEC1, relative to the first atom given in IVEC1.

ORIG1
= starting value of the coordinate, which may be positive or negative. Zero corresponds to the distance given in $DATA.

DISP1
= step size for the coordinate.

NDISP1
= number of steps to take for this coordinate.

There are no reasonable defaults for these keywords, so you should input all of them. ORIG1 and DISP1 should be given in Angstrom.

IVEC2, IGRP2, ORIG2, DISP2, NDISP2 = have the identical meaning as their "1" counterparts, and permit you to make a two dimensional map along two displacement coordinates. If the "2" data are not input, the surface map proceeds in only one dimension.


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