We explore the experimental and simulation results of the formation of defects on the surface of lithium fluoride thin films under irradiation with different mass ions using total current (TC) spectroscopy, secondary ion mass spectroscopy (SIMS), and the Stopping and Range of Ions in Matter (SRIM) software package. A comparative study was carried out with ions of different masses, and inconsistencies in the occurring physical phenomena between our early concepts were found. It is shown that in the case of heavy ions irradiation, they are implanted and appear as substitutional atoms into the bulk of the crystal. For ions with the smallest ion mass, the distribution of interstitial defects is greater on the surface than in the bulk of the crystal. An attempt is made to explain the formation of some defects on the surface (formed peaks in the TC spectra) by the method of computer simulation.