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Keyword category:

Annealing

ANNEAL

ANNEAL — Simulated annealing search for geometric minima

Usage

ANNEAL

Description

The ANNEAL method locates a set of minima on a potential energy surface by a procedure employing a mixture of non-local simulated annealing and gradient minimization. See Chapter 12, Simulated Annealing for discussion of the use of this method as well as an explanation of the dedicated keywords used in the annealing procedure. The energy (Heat of Formation) is minimized and is the criterion of search for ANNEAL. By default, TRUSTE is used in the quenching phase but BFGS, DFP, or EF can be used to override this default. NEWTON may also be specified for a subsequent quenching phase using a full Hessian.

Abbreviation:

ANNE

Requires:

none

Required by:

none

Default value:

none

See also:

GANNEAL, TSANNEAL, MANNEAL, NEWTON.

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
$$ limit - annealing boundaries
  100 100 -180 100 -180 100 -180 100 -180 100 -180 100 -180 100    1
    -180 100 -180 100 -180 100 -180 100 -180 100 -180 100 -180
    100 -180 100 -180
  130 130  180 130  180 130  180 130  180 130  180 130  180 130    2
    180 130  180 130  180 130  180 130  180 130  180 130  180
    130  180 130  180
$$ end of extra data
1

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.
2

These are the upper boundaries of the bond angles and dihedrals (in order as specified) as required for by the annealing keyword LIMIT.
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