Dynamic Force Spectroscopy: Looking at the Total Harmonic Distortion
  Tapping mode atomic force microscopy is a standard technique for inspection and analysis at the nanometer scale. The understanding of the non-linear dynamics of the system due to the tip sample interaction is an important prerequisite for a correct interpretation data acquired by dynamic AFM. Here, the system response in tapping-mode atomic force microscope (AFM) simulated numerically. In the computer model the AFM microcantilever is treated as a distributed parameter system. With this multiple-degree-of-freedom (MDOF) approach the the total harmonic distortion in dynamic AFM spectroscopy is simulated. 
Robert W. Stark