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Appendix A. Keyword Reference |  |
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Appendix A. Keyword Reference | |
STEP1 — Specify step size for first coordinate in reaction grid calculation.
STEP1=n.n
In a two dimensional reaction grid calculation, the two parameters to be used in the grid are defined in the input file by a “-1” as the optimization flags. The step size (in degrees or Angstroms) to be taken along the first grid parameter is set to n.n. The step size to be taken along the second grid parameter is set by STEP2. By default, eleven steps along each parameter are defined, giving a total of 121 points on the grid. The GRID keyword can be used to adjust number of points in each direction. The input structure always represents the center point of the generated grid.
am1 rhf singlet qcscf t=auto step1=0.15 step2=0.15 grad minvis1,5-HEXADIENE INVERSION Rxn grid calculation C 0.000000 0 0.000000 0 0.000000 0 0 0 0 C 1.300000 1 0.000000 0 0.000000 0 1 0 0 C 1.540000 1 130.000000 1 0.000000 0 2 1 0 C 1.540000 -1 120.000000 1 0.000000 1 3 2 1
C 1.540000 1 120.000000 1 0.000000 1 4 3 2 C 2.190000 -1 110.000000 1 0.000000 1 1 2 3
H 1.000000 1 120.000000 1 90.000000 1 1 2 3 H 1.000000 1 120.000000 1 180.000000 1 1 2 7 H 1.000000 1 120.000000 1 -180.000000 1 2 3 4 H 1.000000 1 109.500000 1 120.000000 1 3 4 5 H 1.000000 1 109.500000 1 -120.000000 1 3 4 5 H 1.000000 1 109.500000 1 120.000000 1 4 3 2 H 1.000000 1 109.500000 1 -120.000000 1 4 3 2 H 1.000000 1 120.000000 1 120.000000 1 5 4 3 H 1.000000 1 120.000000 1 90.000000 1 6 5 4 H 1.000000 1 120.000000 1 180.000000 1 6 5 15 0 0.000000 0 0.000000 0 0.000000 0 0 0 0
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A reaction grid calculation will be performed if exactly two of optimization flags are marked with a “-1”. The keywords STEP1 and STEP2 are also required for a reaction grid. By default, TRUSTE will be use to perform the constrained optimization at each of the grid points but this default can be overridden by BFGS, DFP, or EF |
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This is the first reaction coordinate and will be incremented and decremented by the value of STEP1. |
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This is the second reaction coordinate and will be incremented and decremented by the value of STEP2. These two items will be used to construct a grid of points and optimizations will be carried out at each point on the surface. The point given in the geometry definition is the center of the grid and five steps are taken in each direction from this center point. The following list shows the values that the first and second reaction coordinates will take on. The center point is indicated by ×: Step 1
0.79 0.94 1.09 1.24 1.39 1.54 1.69 1.84 1.99 2.14 2.29
1.44 o o o o o o o o o o o
1.59 o o o o o o o o o o o
1.74 o o o o o o o o o o o
S 1.89 o o o o o o o o o o o
t 2.04 o o o o o o o o o o o
e 2.19 o o o o o × o o o o o
p 2.34 o o o o o o o o o o o
2.49 o o o o o o o o o o o
2 2.64 o o o o o o o o o o o
2.79 o o o o o o o o o o o
2.94 o o o o o o o o o o o
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Copyright © 1992-2013 Semichem, Inc. All rights reserved. |
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STEP2 |