相关论文: CF$^+$ excitation in the interstellar medium
To evaluate the effect of turbulent heating in the thermal balance of interstellar clouds, we develop an extension of the log-Poisson intermittency model to supersonic turbulence. The model depends on a parameter, d, interpreted as the…
We aim to obtain accurate rate coefficients for the collisional excitation of CH+ by He for high gas temperatures. The ab initio coupled-cluster [CCSD(T)] approximation was used to compute the interaction potential energy. Cross sections…
Modeling the spectral emission of low-charge iron group ions enables the diagnostic determination of the local physical conditions of many cool plasma environments such as those found in H II regions, planetary nebulae, active galactic…
Isomerism in complex organic molecules provides key insights into the formation mechanisms and physical conditions of the interstellar medium (ISM). Among the C$_2$H$_5$NO isomers, only acetamide and trans-N-methylformamide (trans-NMF) have…
Aims: The large abundances of CH$^+$ in the diffuse interstellar medium (ISM) are a long standing issue of our understanding of the thermodynamical and chemical states of the gas. We investigate, here, the formation of CH+ in turbulent and…
Nitric oxide is an open-shell molecule abundantly detected in the interstellar medium. A precise modeling of its radiative and collisional processes opens the path to a precise estimate of its abundance. We present here the first rate…
The H3+ molecule has been detected in many lines of sight within the central molecular zone (CMZ) with exceptionally large column densities and unusual excitation properties compared to diffuse local clouds. The detection of the (3,3)…
We present very high signal-to-noise ratio absorption-line observations of CN and CH+ along 13 lines of sight through diffuse molecular clouds. The data are examined to extract precise isotopologic ratios of 12CN/13CN and 12CH+/13CH+ in…
Deuterated interstellar molecules frequently have abundances relative to their main isotopologues much higher than the overall elemental D-to-H ratio in the cold dense interstellar medium. The H$_3^+$ and its isotopologues play a key role…
Recent observations of excess radiation at extreme ultraviolet and hard X-ray energies straddling the well known thermal soft X-ray emission have provided new tools and puzzles for investigation of the acceleration of nonthermal particles…
Radiative charge exchange collisions between a carbon atom C(${}^3$P) and a helium ion He+, both in their ground state, are investigated theoretically. Detailed quantum chemistry calculations are carried out to obtain potential energy…
Cross sections and rate coefficients for rovibronic excitation of the CH$^+$ ion by electron impact and dissociative recombination of CH$^+$ with electrons are evaluated using a theoretical approach combining an R-matrix method and…
Interstellar aromatic molecules such as polycyclic aromatic hydrocarbons and polycyclic nitrogen and oxygen bearing molecules are thought to be abundant in the interstellar medium. In this class of molecules, benzonitrile ($c$-C$_6$H$_5$CN)…
The so-called full non-local thermodynamic equilibrium (FNLTE) radiative transfer problem allows us to take into account not only deviations of the radiation field from the Planckian but also deviations of the densities and velocity…
Estimating molecular abundances ratios from the direct measurement of the emission of the molecules towards a variety of interstellar environments is indeed very useful to advance in our understanding of the chemical evolution of the…
Data for inelastic processes due to hydrogen atom collisions with manganese and titanium are needed for accurate modeling of the corresponding spectra in late-type stars. In this work excitation and charge transfer in low-energy Mn+H and…
We examine a sample of 106 galaxies for which the total luminosities of the two fine structure lines $^{3}P_1$$\rightarrow $$^{3}P_{0}$, and $^{3}P_2$$\rightarrow $$^{3}P_{1}$ of neutral atomic carbon (C) are available, and find their…
Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations…
Ammonia is one of the most widely observed molecules in space, and many observations are able to resolve the hyperfine structure due to the electric quadrupole moment of the nitrogen nucleus. The observed spectra often display anomalies in…
Modeling of molecular emission from interstellar clouds requires the calculation of rates for excitation by collisions with the most abundant species. The present paper focuses on the calculation of rate coefficients for rotational…