Understanding the most favourable dimer of HCN for the oligomerization process in the gas phase of interstellar clouds

The dimerization reaction for the formation of HCN dimer from two molecules HCN in the gas phase, has been studied theoretically using density functional theory (DM method at the B3LYP hybrid together with 6-311g(d, p) basis set level. The mechanisms considered for the isomerization pathway from HCN isomer shows that the iminoacetonitrile is the most stable dimer (-6 kcal/mol) and is passing through the smallest barrier energy to be 41 kcal/mol. Consequently, this dimer is energetically and kinetically most favourable, under isolated conditions, for the prebiotic syntheses of amino acid and nucleobase or adenine product by oligomerization process under interstellar conditions. (C) 2016 Elsevier B.V. All rights reserved.