Nitrogen hydrides are at the root of the nitrogen chemistry in interstellar space. The detailed modeling of their gas phase formation, however, requires the knowledge of nuclear-spin branching ratios for chemical reactions involving multiprotonated species. We investigate in this work the nuclear-spin selection rules in both exothermic and near thermoneutral ion–molecule reactions involved in t...

Buckminsterfullerene (C(60)) was recently confirmed as the largest molecule identified in space. However, it remains unclear how and where this molecule is formed. It is generally believed that C(60) is formed from the buildup of small carbonaceous compounds in the hot and dense envelopes of evolved stars. Analyzing infrared observations, obtained by Spitzer and Herschel, we found that C(60) is...

The mechanism for the formation of hexamethylenetetraamine predicts the formation of aminomethanol from the addition of ammonia to formaldehyde. This molecule subsequently undergoes unimolecular decomposition to form methanimine and water. Aminomethanol is the predicted precursor to interstellar glycine, and is therefore of great interest for laboratory spectroscopic study, which would serve as...

Water is crucial for the emergence and evolution of life on Earth. Recent studies water content in early forming planetary systems similar to our own show that an abundant ubiquitous molecule, initially synthesized surfaces tiny interstellar dust grains by hydrogenation frozen oxygen. then enters a cycle sublimation/freezing throughout successive phases system formation, namely, hot corinos pro...

We report precise measurements of ground-state, Lambda-doublet microwave transitions in the hydroxyl radical molecule (OH). Utilizing slow, cold molecules produced by a Stark decelerator we have improved over the precision of the previous best measurement 25-fold for the F'=2-->F=2 transition, yielding (1 667 358 996 +/- 4)Hz, and by tenfold for the F'=1-->F=1 transition, yielding (1 665 401 80...

The existence of NCO(-) anions in the interstellar medium (ISM) has been suggested and searched for over the years but without any formal definitive sighting of that molecule. We discuss in this work the possible formation of either NCO(-) directly or of NCO neutral as a precursor to NCO(-) formation by electron attachment. We follow simple, gas-phase chemical reactions for which the general fe...

Extending previous work (Albrecht & Kegel 1987, Kegel et al. 1993, Piehler & Kegel 1994), we investigated the formation of interstellar molecular lines in a medium with stochastic density and velocity fluctuations. We solved the full NLTE– problem, i.e. the generalized radiative transfer equation simultaneously with the rate equations, for a 6–level CO molecule and a plane-parallel slab geometr...

The first detection of a 36 S-bearing molecule in interstellar space is reported. The J=2−1 and 3−2 transitions of C 36 S have been observed toward eight Galactic molecular hot cores. From a comparison with other optically thin isotopic species of CS, the abundance ratio of 34 S/ 36 S is 115(±17). This is smaller than the solar system ratio of 200 and supports the idea that 36 S is, unlike the ...

The C3 molecule is of fundamental interest to chemists, both as the simplest cumulene and as a prototypical nonrigid system. It is also of great importance in astrophysics, as it now serves as a remote diagnostic of the temperature and density of interstellar clouds. However, high resolution astronomical spectra have uncovered a discrepancy between the observed R(0) transition and the laborator...