I am trying to probe the adsorption of an organic molecule on the surface of Ni oxyphosphate by calculating the Density of states of the adsorbed configuration (generated using adsorption locator) using DMol3. GGA PBE functional is used with DNP basis set. But even after trying multiple approaches the run fails: 

Method 1: ran the calculation for the entire molecule + Ni oxyphosphate slab (around 200 atoms); a warning about additional memory requirement followed by abrupt end of the run is seen. 

Method 2: Increased the memory requirement and ran the calculation with the adsorbed molecule + only top layer of Ni oxyphosphate atoms (total of 120 atoms) this time the error is due to SCF not converging. I tried to modify the 'use symmetry' and 'spin unrestricted/restricted' options, tried to modify smearing, preconditioner and DIIS values but nothing worked. Either the SCF doesn't converge or a memory requirement warning followed by an unexpected end of run happens. 

Kindly give me suggestions on how to run a successful calculation.