import molecule_lib as mlb
monomer_mol = mlb.read_xyz("NUCLEOTIDE.xyz")
dimer_mol = monomer_mol.add_coords(molecule = monomer_mol,
absorbent_reference = "Bottom",
surface_reference = "Top",
dist = 4,
axis = "z")
dimer_mol.to_xyz("NUCLEOTIDE_DIMER.xyz")