I am trying to calculate the Fermi level of a DNA-graphene system. I was able to get the calculations for graphene and DNA strand to converge separately. However, when I try to calculate the same for DNA-graphene system, the SCC cycles do not converge even after multiple restarts. Any information on why is this happening would be much appreciated.
The input file can be found here.
Further context: The coordinates are obtained from clustering of a Molecular Dynamics trajectory, and the graphene segment and DNA strand is cut out from the original full sheet and 20-nucleotide long single-strand DNA from the MD trajectory. Therefore, i am not allowed to perform an extra geometry optimization to relax the structure.