Manual:DIRAC:OPTIMIZE
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*OPTIMIZE -- Geometry optimization directives
This section controls the geometry optimization. The geometry optimization algorithm is based on the one of DALTON. The directives are therefore the same except for these few changes:
- No second-order algorithms are available since the molecular Hessian is not implemented.
- A few new keywords have been introduced (see below).
If .PROPERTIES
(.ANALYZE)
is specified in the job input section together with
.OPTIMIZE,
then the property (analysis) module
is called in each optimization iteration and at the converged geometry.
In each iteration, the properties (analysis) requested under **PROPERTIES (**ANALYZE) are calculated, and at the converged geometry the properties (analysis) given in **PRP F (**ANA F) are calculated.
.NO SKIP
The "trick" is by default activated in a geometry optimization, since when the current geometry is far away from the equilibrium, e.g. the norm of the gradient is, say, 1.0, then there is no need to calculate the LS and/or SS two-electron gradient because they have a norm of, say 0.001.
This keywords forces the LS and SS two-electron gradient to always be evaluated in all geometry iterations (depending on the integral flag).
.NUMGRA
Force the use of numerical gradient in geometry optimization, e.g. in Hartree-Fock calculations.
.TWOGRD
Default: Include LL, SL, and SS integral contributions to the gradient (1 = on; 0 = off).
.TWOGRD 1 1 1
.BAKER
Baker's convergence criteria [J. Comp. Chem. 14(1993) 1085] will be used.
.1STORD
Default 1st order method will be used: BFGS update.
Thresholds
Depending on convergence criterias for energies and gradients the values of the thresholds may be automatically adjusted.
.GRADIE
Convergence threshold for the gradient. Default 1.0D-5.
.ENERGY
Convergence threshold for the energy. Default 1.0D-06.
.STEP T
Convergence threshold for the step. Default 0.10D-04.
