Initially, a ssDNA molecule A6 with 6 bases of adenine was positioned below the graphene nanopore. As reported previously, we then used a harmonic spring with one end attached to the phosphorus atom of the first nucleotide and the other end moving at a constant velocity v to simulate the pulling by an atomic force microscope (AFM) tip. The pulling force on the spring was recorded during SMD simulations. Very recently, the force spectroscopy has been experimentally determined when an AFM tip pulls a ssDNA through a carbon nanotube pore. Various alternative approaches for measuring force spectroscopy for DNA translocation through nanopores are also experimentally available such as using optical or magnetic tweezers.