I am building a cluster of anatase TiO2 unit cell about 100 atoms and trying to make a single point energy calculation via Dmol3 code, but everytime i get the "SCF does not converge" error.

Can you give an idea about doing a single point energy calculation via Dmol3. I guess the error is becouse of the non periodicity, but then , tried to calculate by putting the cluster in a supercell but it did not work to.

Waiting for a quick response, thanks.