Study Polyoxovanadates with XTB

[crispom]

I try to optimise the structure of polyoxovanadate [H4V10O28]-- with XTB.
The structure is stable at DFT and MP2 level. The problem it is the optimisation disrupt the structure of the ion until it has a too strange structure and the SCF procedure does not converge. All V atoms have the +5 oxidation state and the ion is diamagnetic.
Somebody has experience with compounds of this nature or other polyxometalates? There are SCF parameters that I can stress?

[haneug]

Hi,
I can recommend the to try the procedures outlined here: #548 (comment)
Best,
Hagen