Molecular dynamics simulation of amorphization in forsterite by cosmic rays

R. DEVANATHAN; P. DURHAM; J. DU; L.R. CORRALES; E.M. BRINGA

NUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH B - BEAM INTERACTIONS WITH MATERIALS AND ATOMS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2007 vol. 255 p. 172 - 176

0168-583X

We have examined cosmic ray interactions with silicate dust grains by simulating a thermal spike in a 1.25 million atom forsterite (Mg2SiO4) crystal with periodic boundaries. Spikes were generated by giving a kinetic energy of 1 or 2 eV to every atom within a cylinder of radius 1.73 nm along the [0 0 1] direction. An amorphous track of radius ∼3 nm was produced for the 2 eV/atom case, but practically no amorphization was produced for 1 eV/atom because of effective dynamic annealing. Chemical segregation was not observed in the track. These results agree with recent experimental studies of ion irradiation effects in silicates, and indicate that cosmic rays can cause the amorphization of interstellar dust.