Electron irradiation of a-C:H deposits:Effects of cosmic rays on interstellar carbonaceous dust

Abstract

Deposits of plasma-generated hydrogenated amorphous carbon, termed a-C:H or HAC, were irradiated with 5 keV electrons to simulate the electron cascades produced in the interaction of cosmic rays with solid particles. A destruction rate for CH bonds was derived from the evolution of the 3.4 microns IR absorption band. The results are in good agreement with the most recent ion irradiation data and show that cosmic rays alone cannot justify the disappearance of the 3.4 microns band in the interior of dense clouds.