The composition of interstellar molecular clouds
Journal or Book Title
SPACE SCIENCE REVIEWS
We consider four aspects of interstellar chemistry for comparison with comets: molecular abundances in general, relative abundances of isomers (specifically, HCN and HNC), ortho/para ratios for molecules, and isotopic fractionation, particularly for the ratio hydrogen/deuterium. Since the environment in which the solar system formed is not well constrained, we consider both isolated dark clouds where low mass stars may form and the "hot cores" that are the sites of high mass star formation. Attention is concentrated on the gas phase, since the grains are considered elsewhere in this volume.
Irvine, William M., "The composition of interstellar molecular clouds" (1999). SPACE SCIENCE REVIEWS. 201.