Spectroscopic properties of interstellar molecules: Theory and experiment

Over the past two decades, the identification and characterisation of interstellar molecules has often benefitted from a fruitful interplay between theoretical chemistry, laboratory spectroscopy and ( radio) astronomy. The article reports on various examples of this sort, concentrating on carbon chains which represent the most prominent structural motif among currently known interstellar molecules. Results of large-scale coupled cluster calculations are reported for cyanopolyynes (HC2n+1N) up to n = 5, the corresponding radicals C2n+1N, linear silicon carbides ( SiCn), carbon-sulfur and pure carbon chains. Throughout, detailed comparison with experimental data is made wherever possible.