Defined in
ITER.

Default value
0.0001 kcal/mole
Basic Test
Change in energy in kcal/mole on successive
iterations is less than SCFCRT.

Exceptions:
If PRECISE is specified,
SCFCRT=0.000001

If a polarization calculation
SCFCRT=1.D11

If a FORCE calculation
SCFCRT=0.0000001

If SCFCRT=n.nnn is specified
SCFCRT=n.nnn

If a BFGS optimization, SCFCRT becomes a function

of the difference between the current energy and

the lowest energy of previous SCFs.
Secondary tests: (1) Change in density matrix elements on two
successive iterations must be less than 0.001
(2) Change in energy in eV on three successive
iterations must be less than 10 x SCFCRT.
 142 
CRITERIA
Page 92
9.2
GEOMETRIC OPTIMIZATION CRITERIA
Name:
TOLERX
"Test on X Satisfied"
Defined in
FLEPO
Default value
0.0001 Angstroms
Basic Test
The projected change in geometry is less than
TOLERX Angstroms.
Exceptions
If GNORM is specified, the TOLERX test is not used.
Name:
DELHOF
"Herbert's Test Satisfied"
Defined in
FLEPO
Default value
0.001
Basic Test
The projected decrease in energy is less than
DELHOF Kcals/mole.
Exceptions
If GNORM is specified, the DELHOF test is not used.
Name:
TOLERG
"Test on Gradient Satisfied"
Defined in
FLEPO
Default value
1.0
Basic Test
The gradient norm in Kcals/mole/Angstrom is less
than TOLERG multiplied by the square root of the
number of coordinates to be optimized.
Exceptions
If GNORM=n.nnn is specified, TOLERG=n.nnn divided
by the square root of the number of coordinates
to be optimized, and the secondary tests are not
done.
If LET is not specified, n.nnn is reset to
0.01, if it was smaller than 0.01.
If PRECISE is specified, TOLERG=0.2
If a SADDLE calculation, TOLERG is made a function
of the last gradient norm.
Name:
TOLERF
"Heat of Formation Test Satisfied"
Defined in
FLEPO
Default value
0.002 Kcal/mole
Basic Test
The calculated heats of formation on two successive
cycles differ by less than TOLERF.
Exceptions
If GNORM is specified, the TOLERF test is not used.
Secondary Tests For the TOLERG, TOLERF, and TOLERX tests, a
second test in which no individual component of the
gradient should be larger than TOLERG must be
satisfied.
Other Tests
If, after the TOLERG, TOLERF, or TOLERX test has been
satisfied three consecutive times the heat of
formation has dropped by less than 0.3Kcal/mole, then
the optimization is stopped.
Exceptions
If GNORM is specified, then this test is not performed.
Name:
TOL2
 143 
CRITERIA
Page 93
Defined in
POWSQ
Default value
0.4
Basic Test
The absolute value of the largest component of the
gradient is less than TOL2
Exceptions
If PRECISE is specified, TOL2=0.01
If GNORM=n.nn is specified, TOL2=n.nn
If LET is not specified, TOL2 is reset to
0.01, if n.nn was smaller than 0.01.
Name:
TOLS1
Defined in
NLLSQ
Default Value
0.000 000 000 001
Basic Test
The square of the ratio of the projected change in the
geometry to the actual geometry is less than TOLS1.
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 jane smith
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