LIMIT

LIMIT
	Appendix A. Keyword Reference

Description

This keyword causes periodic boundaries to be entered from a special section of the input file. When LIMIT is invoked, the user must supply the boundary values to be used for each optimizable coordinate in a data section following the molecular geometry. This data section is initiated by the string “$$ limit - annealing boundaries” (or simply “$$ limit”) and followed by N lower bounds for the optimizable geometric parameters in order of their definition in the input file, followed by N upper bounds in the same fashion. The data is entered free format and may occupy more than one line. Use of the LIMIT keyword is strongly recommended for efficiency in searching the potential energy surface. Units are angstroms and degrees. AUTOLIMIT is similar to LIMIT but the bounds are supplied automatically.

Abbreviation:

none

Requires:

ANNEAL, GANNEAL, TSANNEAL, or MANNEAL.

Default value:

none

Examples:

Input File (annealing/anneal1.dat):

  am1 rhf singlet t=auto anneal truste pen2 ncheck=10 noxyz limit
Cyclohexane
Annealing on cyclic system: PEN2, NCHECK, LIMIT
 C              0.000000  0    0.000000  0    0.000000  0    0    0    0
 C              1.520880  0    0.000000  0    0.000000  0    1    0    0
 C              1.520880  0  112.706930  1    0.000000  0    2    1    0
 C              1.520880  0  112.706930  1   -7.376720  1    3    2    1
 C              1.520880  0  112.706930  1  -46.310020  1    1    2    3
 C              1.520880  0  112.706930  1   50.819480  1    5    1    2
 H              1.121200  0  112.384140  1   75.006870  1    1    2    3
 H              1.121200  0  112.384140  1 -167.313050  1    1    2    3
 H              1.121200  0  112.384140  1  121.019560  1    2    3    1
 H              1.121200  0  112.384140  1 -121.144800  1    2    3    1
 H              1.121200  0  112.384140  1  113.455200  1    3    2    1
 H              1.121200  0  112.384140  1 -128.802830  1    3    2    1
 H              1.121200  0  112.384140  1  177.862400  1    4    3    2
 H              1.121200  0  112.384140  1  -63.807980  1    4    3    2
 H              1.121200  0  112.384140  1   57.505850  1    5    4    3
 H              1.121200  0  112.384140  1 -154.797280  1    5    4    3
 H              1.121200  0  112.384140  1  121.566360  1    6    5    4
 H              1.121200  0  112.384140  1 -122.040500  1    6    5    4
 0              0.000000  0    0.000000  0    0.000000  0    0    0    0
$$ limit - annealing boundaries
  100 100 -180 100 -180 100 -180 100 -180 100 -180 100 -180 100    
    -180 100 -180 100 -180 100 -180 100 -180 100 -180 100 -180 
    100 -180 100 -180
  130 130  180 130  180 130  180 130  180 130  180 130  180 130    
    180 130  180 130  180 130  180 130  180 130  180 130  180 
    130  180 130  180
$$ end of extra data

	These are the lower boundaries of the bond angles and dihedrals (in order as specified) as required for by the annealing keyword LIMIT. Note that no values for the bond lengths are included. This is because none of them are marked for optimization.
	These are the upper boundaries of the bond angles and dihedrals (in order as specified) as required for by the annealing keyword LIMIT.

Name

Synopsis