I am trying to assess the solvent effects on the equilibrium structure of a relatively large copper complex with over 100 atoms. The molecule is not really globular, so the cavity is bound to be
complicated. Turbomole did issue a warning of 28 disjunct cavities, so following its advise I have use the use_contcav option in the COSMO section of the control file.
I have use the optimised radii for all atoms except from Cu and P, which are, however, in the centre of the molecule so the non-optimum atomic radii in their case should be of secondary importance.
The SCF energy behaves quite chaotically (jumping up and down by even several Hartees) despite any efforts to stabilise the convergence (increased damping, virtual orbital shift, fermi smearing).
I have noticed that it is the Ediel value changes drastically (from 0.9 to 8 or 9) and rather unsystematically with every step of the SCF procedure. I gather that this may be the reason for the overall instability of the SCF procedure.
However, I do not know how to circumvent this problem. Would be grateful for any assistence in the matter.
My very best regards
Marcin