Boson peak in neutron-irradiated quartz crystal

In this paper we present Raman measurements in the low-frequency range from 15 to 150 cm(-1), which were performed in quartz crystal irradiated with fast neutron (irradiation dose 4.7 x 10(19) n/cm(2)). This dose leaves the sample mainly crystalline (70%). Our measurements revealed the presence of the boson peak at 60 cm(-1). The soft-potential model explains the boson peak in amorphous solids by the inelastic scattering of light by soft quasilocal harmonic oscillators (HO). Our observation shows that the irradiation dose 4.7 x 10(19) n/cm(2) is sufficient to create a concentration of quasilocal HO, which is necessary for the appearance of the boson peak. (C) 2002 Elsevier Science B.V. All rights reserved.