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Alex Granovsky
gran@classic.chem.msu.su

I forgot to mention that such solutions of SCF equations are usually
have no or very little physical sense and could be caused by deficient
ECPs, basis sets, DFT functionals, multi-configuration character of
electronic states, or both. Out of interest I have checked your
system with quite a different functional, namely sogga11x, and found
that it results in solution that obeys the aufbau principle.
I'd suggest you to consider trying MCSCF for your model system.

All the best,
Alex






On Tue Jun 13 '17 8:48pm, Alex Granovsky wrote
----------------------------------------------
>Dear Pedro,

>the real reason of convergence problems you encountered
>is that lowest-energy SCF solution for your system does not obey
>the aufbau principle. Firefly presently has some problems when
>dealing with such types of SCF solutions hence the poor SCF
>convergence and some problems when reusing previously converged MOs.

>All the best,
>Alex
>
>
>
>
>On Thu Jun 8 '17 1:44pm, Pedro Silva wrote
>------------------------------------------
>>The attached input is an (apparently) streaightforward instance of feeding a converged $VEC group at the starting geometry. However, the SCF convergence at the initial point (corresponding to the $VEC group read with guess=moread) is exceedingly slow: more than 100 SCF steps are needed, even with soscf=.t. switched on. Since I do not often find these problems, and the most salient difference between my "usual" cases and this instance is the use of ecp=read, I wonder whether there is some problem arising from the interplay of these groups.