Ultraviolet irradiation of the polycyclic aromatic hydrocarbon (PAH) naphthalene in H2O.: Implications for meteorites and biogenesis

The polycyclic aromatic hydrocarbon (PAH) naphthalene was exposed to ultraviolet radiation in H2O ice under astrophysical conditions, and the products were analyzed using high performance liquid chromatography. As we found in our earlier studies on the photoprocessing of coronene in H2O ice, aromatic alcohols and ketones (quinones) were formed. The regiochemistry reported here leads to specific predictions of the relative abundances of oxidized naphthalenes that should exist in meteorites. Since oxidized PAHs are present in meteorites and interplanetary dust particles, and ubiquitous in and fundamental to biochemistry, the delivery of such extraterrestrial molecules to the early Earth may have played a role in the origin and evolution of life. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.