Related papers: Ortho-para-H$_2$ conversion processes in astrophys…

New insights into the formation of interstellar formamide, a species of great relevance in prebiotic chemistry, are provided by electronic structure and kinetic calculations for the reaction NH2 + H2CO -> NH2CHO + H. Contrarily to what…

Energy exchange processes play a crucial role in the early Universe, affecting the thermal balance and the dynamical evolution of the primordial gas. In the present work we focus on the consequences of a non-thermal distribution of the…

Using the Expanded Very Large Array, we have mapped the vicinity of the Orion BN/KL Hot Core with sub-arcsecond angular resolution in seven metastable inversion transitions of ammonia: (J,K)=(6,6) to (12,12). This emission comes from levels…

Astrochemical models of interstellar clouds, the sites of stars, and planet formation require information about spin-state chemistry to allow quantitative comparison with spectroscopic observations. In particular, it is important to know if…

$Aims$: We revisit with new augmented accuracy the theoretical dynamics of basic isotope exchange reactions involved in the $^{12}$C/$^{13}$C, $^{16}$O/$^{18}$O, and $^{14}$N/$^{15}$N balance because these reactions have already been…

The spatial distribution of the chemical reservoirs in protoplanetary disks is key to elucidate the composition of planets, especially habitable ones. However, the partitioning of the main elements among the refractory and volatile phases…

The nuclear-spin chemistry of interstellar water is investigated using the University of Grenoble Alpes Astrochemical Network (UGAN). This network includes reactions involving the different nuclear-spin states of the hydrides of carbon,…

A continuous supersonic flow reactor has been used to measure rate constants for the C + NH3 reaction over the temperature range 50 to 296 K. C atoms were created by the pulsed laser photolysis of CBr4. The kinetics of the title reaction…

Rate coefficients for rotational transitions in H_2 induced by H_2 impact are presented. Extensive quantum mechanical coupled-channel calculations based on a recently published (H_2)_2 potential energy surface were performed. The potential…

The rate constants for the formation, destruction, and collisional excitation of SH$^+$ are calculated from quantum mechanical approaches using two new SH$_2^+$ potential energy surfaces (PESs) of $^4A''$ and $^2A''$ electronic symmetry.…

Nitrogen bearing species are common tracers of the physical conditions in a wide variety of objects, and most remarkably in dark clouds. The reservoir of gaseous nitrogen is expected to be atomic or molecular, but none of the two species…

Rotational transitions in molecular hydrogen collisions are computed. The two most recently developed potential energy surfaces for the H2-H2 system are used from the following works: 1) A.I. Boothroyd, P.G. Martin, W.J. Keogh, M.J.…

The gas-phase reaction of $\mathrm{O}+\mathrm{H}_3^+$ has two exothermic product channels, $\mathrm{OH}^+ +\mathrm{H}_2$ and $\mathrm{H}_2\mathrm{O}^+ +\mathrm{H}$. In the present study, we analyze experimental data from a merged-beams…

The first experimental study of the low-temperature kinetics of the gas-phase reaction of NH2 with formaldehyde (CH2O) has been performed. This reaction has previously been suggested as a source of formamide (NH2CHO) in interstellar…

The rate constants required to model the OH$^+$ observations in different regions of the interstellar medium have been determined using state of the art quantum methods. First, state-to-state rate constants for the H$_2(v=0,J=0,1)$+…

Spitzer-IRS maps of H_2 pure rotational lines from S(0) to S(7) in 3 outflows from Class 0 sources - L1448, BHR71, and NGC2071 - are presented. These lines are used, in conjunction with available rovibrational, near-IR H_2 lines, to probe…

Context: Despite the low elemental deuterium abundance in the Galaxy, enhanced molecular D/H ratios have been found in the environments of low-mass star-forming regions and, in particular, the Class 0 protostar IRAS 16293-2422. Aims: The…

Hydrogenation reactions of CO in inter- and circumstellar ices are regarded as an important starting point in the formation of more complex species. Previous laboratory measurements by two groups on the hydrogenation of CO ices resulted in…

Water is an important reservoir species for oxygen in interstellar space and plays a key role in the physics of star formation through cooling by far-infrared emission. Whilst water vapour is present at high abundances in the outflows of…

Spectrally-resolved observations of three pure rotational lines of H$_2$, conducted with the EXES instrument on SOFIA toward the classic bow shock HH7, reveal systematic velocity shifts between the S(5) line of ortho-H$_2$ and the two…