Si-H bonds produced by ion implantation in silicon and frozen silanes

In a recent paper Pendleton et al. (1998) present new spectra of embedded protostars which exhibit a broad absorption feature near 4.62 mu m (2165 cm(-1)). In the literature this band is referred to as the "X(C=N)" band. However Pendleton et al. (1998) cannot exclude the possibility of a different identification (such as an Si-H related compound) for which they claim the need of experimental data. To contribute to fulfill this request we present here new laboratory results on: (I) the formation of Si-H bonds induced by implantation of 30 keV H+, H-2(+) and CH+ ions into silicon and (2) the production of Si-H-containing refractory species by ion irradiation (60 keV Ar ions) of frozen dichlorosilane (SiCl2H2). The obtained results and others already available in the literature have been compared with astronomical observations. Even if we are aware that the sample we consider here is far from being complete, we suggest that it is possible to exclude that a refractory species containing Si-H groups can be responsible for the interstellar feature.