SPECIFIC SEARCH FOR SOLID STATE AND GAS PHASE FEATURES.

this proposal is devoted to the study of interaction between the gas and the solid phases in dense molecular clouds. in addition we wish to detect weak solid state features that will help to establish a link between observations and our laboratory simulations. preliminary results of our iso proposals (mmdusty1 and solsta) have clearly shown that, in the line of sight of embedded protostars, molecular ices made of simple molecules (h2o, co, co2, ch4) are easily detected. superimposed to the broad solid state features, gas phase lines of the same molecules (especially h2o and co2) have been observed. revisiting our goals, we propose, using sws aot6 in some well defined ranges to obtain spectra of the cold molecular foreground in the line of sight of a protostar. these ranges fall in the rotationvibration lines of h2o, co, co2 and ch4. we have also selected a few ranges pertaining to new solid state features in the 3045 micron range seen in two of our objects. the ultimate goal is to understand the role of grains in the chemistry of molecular clouds and gain some insight in the mineral composition of the silicate cores of the grains. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]