| Abstract : | CN, CH and CH+ were the first molecules to be detected in space. They were detected in the late 1930s via electronic spectroscopy. The prevailing idea at that time was that the interstellar medium (ISM) is predominantly atomic and is interspersed with insignificant and diffuse molecular clouds. It took approximately another 30 years in ~ 1967, whence the detection of a signal corresponding to ammonia inversion in the microwave region helped us realize that the ISM also comprises of dense molecular clouds. Since then, about 300 molecules have been detected in space as of January 2024. The Cologne Database of Molecules in Space (CDMS) provides a comprehensive list of these molecules. The molecules range from inorganic metal bearing substances to organic molecules comprising of all or some of the following atoms - C, N, H, O, S, and P. There is a rich structural variety in the interstellar molecules detected - saturated, unsaturated, cyclic, charged - cationic and anionic, open-shell free radicaloid, aromatic monocyclic and polycyclic, carbon-allotropic structures being the dominant structural motifs. How could these molecules have evolved in space? What might have been their formation mechanisms? In what region of the ISM may they have formed? What clues do they hold about molecular evolution in the universe? These and some other related aspects will be presented in this talk. |
