  We present experimental studies on the photoionization and photodissociation
processes (photodestruction) of gaseous amino acids and nucleobases in
interstellar and interplanetary radiation conditions analogs. The measurements
have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS),
employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set
up basically consists of a time-of-flight mass spectrometer kept under high
vacuum conditions. Mass spectra were obtained using photoelectron photoion
coincidence technique. We have shown that the amino acids are effectively more
destroyed (up to 70-80%) by the stellar radiation than the nucleobases, mainly
in the VUV. Since polycyclic aromatic hydrocarbons have the same survival
capability and seem to be ubiquitous in the ISM, it is not unreasonable to
predict that nucleobases could survive in the interstellar medium and/or in
comets, even as a stable cation.
