相关论文: Deuterated hydrogen chemistry: Partition functions…
Partition functions and dissociation equilibrium constants are presented for 291 diatomic molecules for temperatures in the range from near absolute zero to 10000 K, thus providing data for many diatomic molecules of astrophysical interest…
The H3+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H3+ impossible, but lead to large…
At the low temperatures ($\sim$10 K) and high densities ($\sim$100,000 H$_2$ molecules per cc) of molecular cloud cores and protostellar envelopes, a large amount of molecular species (in particular those containing C and O) freeze-out onto…
The rate coefficients of various isotopic variations of the H2+ + H2 and H3+ + H2 reactions in the 10-250 K temperature range were measured using a cryogenic 22 pole radio frequency ion trap. The processes involving diatomic ions were found…
We present the modeling results of deuterium fractionation of water ice, H2, and the primary deuterium isotopologues of H3+ adopting physical conditions associated with the star and planet formation process. We calculated the deuterium…
The surface formation of NH3 and its deuterated isotopologues - NH2D, NHD2, and ND3 - is investigated at low temperatures through the simultaneous addition of hydrogen and deuterium atoms to nitrogen atoms in CO-rich interstellar ice…
Deuterium enhancement of monodeuterated species has been recognized for more than 30 years as a result of the chemical fractionation that results from the difference in zero point energies of deuterated and hydrogenated molecules. The key…
The triatomic hydrogen ion H3+ is one of the most important species for the gas phase chemistry of the interstellar medium. Observations of H3+ are used to constrain important physical and chemical parameters of interstellar environments.…
Despite low elemental abundance of atomic deuterium in interstellar medium (ISM), observational evidences suggest that several species in gas-phase and in ices could be heavily fractionated. We explore various aspects of deuterium…
A close coupling quantum-mechanical calculation is performed for rotational energy transfer in a HD+HD collision at very low energy, down to the ultracold temperatures: $T \sim 10^{-8}$ K. A global six-dimensional H$_2$-H$_2$ potential…
Context. In dffuse interstellar clouds the excitation temperature derived from the lowest levels of H$^+_3$ is systematically lower than that derived from H2. The differences may be attributed to the lack of state-specific formation and…
Deuteron-deuteron elastic scattering and transfer reactions in the energy regime above four-nucleon breakup threshold are described by solving exact four-particle equations for transition operators. Several realistic nuclear interaction…
We investigate the dissociation and ionization equilibria of deuterium fluid over a wide range of temperatures and densities. The partition functions for molecular and atomic species are evaluated, in a statistical-mechanically consistent…
The deuterium fractionation of gas-phase molecules in hot cores is believed to reflect the composition of interstellar ices. The deuteration of methanol is a major puzzle, however, because the isotopologue ratio [CH2DOH]/[CH3OD], which is…
We present theoretical thermally-averaged rate constants for vibrational and rotational (de-)excitation of the H3+ ion by electron impact. The constants are calculated using the multi-channel quantum-defect approach. The calculation…
Observations of deuterated species are useful in probing the temperature, ionization level, evolutionary stage, chemistry, and thermal history of astrophysical environments. The analysis of data from ALMA and other new telescopes requires…
We use spectra and maps of the $J=1-0$ and $J=2-1$ DCO$^{+}$, DCN, DNC, $\rm N_2D^+$ lines and $1_{11}-1_{01}$ ortho- and para-NH$_{2}$D lines, obtained with the IRAM-30m telescope, as well as observations of their hydrogenated…
A microscopic formalism for describing observed cross sections for deuteron breakup by three-nucleon nuclei was developed on the basis of the diffraction nuclear model. A general formula that describes the amplitude for the reaction…
The chemical evolution in high-mass star-forming regions is still poorly constrained. Studying the evolution of deuterated molecules allows to differentiate between subsequent stages of high-mass star formation regions due to the strong…
An ever growing number of observational and theoretical evidence suggests that the deuterated fraction (column density ratio between a species containing D and its hydrogenated counterpart, Dfrac) is an evolutionary indicator both in the…