[phenixbb] RMSD limit for negative eletron density

Dear all, I am solving a structure at 1.28 Å. On the ligand, there are some patches of negative electron density till 3.5 RMSD. It will be highly appreciated if someone can tell the maximum RMSD of allowed negative electron density in structure. Thank you! With regards, Bishal Singh PhD student German cancer research center (DKFZ) University of Heidelberg, Germany