The standard MOLPRO convergency criterion requires the maximum component of the
gradient to be less then
[a.u.] and the maximum energy change
to be less than
[H] *or* the maximum component of the
gradient to be less then
[a.u.] and the maximum component of the step
to be less then
[a.u.].

It is also possible to use the convergency criterion of the Gaussian program package. It is somewhat weaker than the MOLPRO criterion and requires the maximum component of the gradient to be less then [a.u.] and the root mean square (RMS) of the gradient to be less then [a.u.] as well as the maximum component of the optimization step to be less then [a.u.] and the RMS of the optimization step to be less then [a.u.].

`MAXIT`=*maxit*- maximum number of optimization cycles. The default is 50.
`GRADIENT`=*thrgrad*- required accuracy of the optimized gradient. The default is .
`ENERGY`=*threnerg*- required accuracy of the optimized energy. The default is .
`STEP`=*thrstep*- convergence threshold for the geometry optimization step. The default is .
`BAKER`- (logical). Use Baker's convergency criteria (see J. Baker,
*J. Comp. Chem.***14**,1085 (1993)). `GAUSSIAN`- (logical). Use Gaussian convergency criteria.
`SRMS`=*thrsrms*- sets (for Gaussian convergency criterion) the required accuracy of the RMS of the optimization step. The default is .
`GRMS`=*thrgrms*- sets (for Gaussian convergency criterion) the required accuracy of the RMS of the gradient. The default is .
`FREEZE`=*thrfreez*- Freeze DFT grid and domains in local calculations if the step length is smaller than
*thrfreez*(default 0.01).

Note: The defaults for the convergence parameters can also be changed by using a global `GTHRESH` directive, i.e.

`GTHRESH`, `OPTSTEP`=*step*, `OPTGRAD`=*grad*, `ENERGY`=*energy*;

molpro@molpro.net 2018-10-21