PC GAMESS/Firefly PES scan documentation

$SURF group (relevant for RUNTYP=SURFACE/RSURFACE)

This group allows you to probe a potential energy surface along a grid of points. 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 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.

Specific to PC GAMESS/Firefly are:

• RUNTYP=RSURFACE (relaxed scan)
• Extensions to allow use of internal coordinates
• VECT1, VECT2, NORMV, NSURF keywords

VECT1 and VECT2 are double precision arrays containing coefficients of the Cartesian or internal coordinates forming displacements to scan, with the numbering scheme the same as of IFREEZ array in $STATPT. VECT1 (and VECT2) runs should be used in conjunction with DISP_i and NDISP_i. ORIG_i are also allowed.

RSURFACE runs should use ifreez in $STATPT to manually freeze the same Cartesian/internal coordinates or their combinations which are selected to scan in $surf via VECT1/VECT2. This is not required for non-relaxed surface runs.

NORMV is seldom used and means to renorm vectors defined via VECT1 or VECT2 to unity.

NSURF controls multiple PES construction for multistate jobs like state-averaged MCSCF.

Press to view sample input file

Press to view sample input file for GAMESS (US) style relaxed scans using DLCs

Download additional samples

Download Firefly-specific samples on scans over internal coordinates using DLCs

See also:

• Density Functional Theory
• Configuration Interaction Singles
• CI and Multi-Configuration SCF
• New MP2 gradient code documentation
• Multicore, SMP and HTT support
• P2P Parallel Mode Communication Interface, Dynamic Load Balancing, and large-scale MP2 Energy code
• Parallel Linux Instructions: list of supported MPI implementations
• Parallel Windows Instructions: list of supported MPI implementations/bindings

Last updated: March 18, 2009