The temperature of a specimen rises when the electron beam interacts with it, producing ionization and excitation of atoms and breaking molecular bonds. Energy loss in bulk materials is ultimately converted to heat, but for small particles some of the energy escapes. Of the energy lost by the electrons in the incident beam, that which is absorbed by the specimen and degraded to heat includes oscillations of valence electrons, the kinetic energy of low-energy secondary electrons, and radiationless recombination of ionized atoms or moiecuies. Energy not absorbed includes brehmsstrahlung, characteristic x-rays, and the kinetic energy of higher-energy secondary electrons. Glaeser (1979) estimated that 50% of the energy loss is confined to a distance of about 5 nm from the track of the incident electron, while the other 50% is largely due to secondary electrons having 0.5 to 5 keV kinetic energy.