A THEORETICAL STUDY ON THE INTERSTELLAR SYNTHESIS OL H sub(2)NCS super(+) AND HNCSH super(+) CATIONS

• Published in: The Astrophysical journal Vol. 792; no. 2; pp. 1 - 9
• Main Authors: Gronowski, Marcin, Kolos, Robert
• Format: Journal Article
• Language: English
• Published: 10.09.2014
• Subjects: Cationic; Cations; Grounds; Interstellar; Mathematical models; Radio spectroscopy; Synthesis
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/792/2/89

HNCS and NCSH molecules, recently discovered in the interstellar medium, are likely formed via the dissociative recombination of H sub(2)NCS super(+) or HNCSH super(+) isomeric ions. Interstellar synthesis of the latter is discussed on theoretical grounds. The analysis of relevant potential energy surfaces suggests a key role for chemical processes in which CSH super(+) or HCS super(+) cations (most likely formed in (ProQuest: Formulae and/or non-USASCII text omitted) collisions) react with NH sub(2) or NH sub(3). The astrochemical kinetic database (kida.uva.2011), appended with 7 sulfur-bearing molecules and 48 corresponding reactions, has been applied to model the evolution of HNCS, NCSH, and their cationic precursors in a quiescent molecular cloud. Based on the model and on spectroscopic predictions, for an object like TMC-1, we expect the total intensity of H sub(2)NCS super(+) microwave lines to be comparable to that observed for HSCN. Theoretically derived molecular parameters, of interest for radio spectroscopy, are given for the most stable cations sharing the H sub(2)NCS super(+) stoichiometry.