title: The rovibrational nature of cis- and trans-HNNS: A possible nitrogen molecule progenitor.
abstract: The HNNS radical has been promoted recently as a viable intermediate in the interstellar creation of the spectroscopically elusive nitrogen molecule. Any confirmation of this pathway or utilizing HNNS as a tracer of N2depends upon the ability to observe the radical intermediate whether in the laboratory or in the interstellar medium. Established and accurate quantum chemical procedures are employed here to produce spectroscopic constants, fundamental vibrational frequencies, and intensities that can be utilized for any possible detection of HNNS. While trans-HNNS is confirmed here to be 3.0 kcal/mol lower in energy than cis-HNNS, the latter will be more readily observed rotationally due to its significantly larger dipole moment. The N-N bond in cis-HNNS is stronger than in trans-HNNS, and earlier work has suggested that cis-HNNS is more useful in the creation of N2from NH and NS. Hence, the detection of cis-HNNS may be of greater value anyway. Furthermore, the N-N stretch in either conformer is also exceptionally bright and will occur in the mid-infrared with nearly 30 cm-1separating the fundamentals of the two conformers. Finally, the low isomerization barrier can be affected significantly upon deuteration also making ND an interesting consideration as a starting material in the interstellar formation of N2.
authors.affiliation: Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Fortenberry