The rotational excitation of HCN and HNC by He: new insights on the HCN/HNC abundance ratio in molecular clouds
@article{Sarrasin2010TheRE, title={The rotational excitation of HCN and HNC by He: new insights on the HCN/HNC abundance ratio in molecular clouds}, author={E. Sarrasin and Dahmani Abdallah and Michael Wernli and A. Faure and Jos{\'e} Cernicharo and F. Lique}, journal={Monthly Notices of the Royal Astronomical Society}, year={2010}, volume={404}, pages={518-526} }
Modelling 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 excitation of the hydrogen cyanide (HCN) and hydrogen isocyanide (HNC) molecules in their ground vibrational state in collision with He. The calculations are based on new two-dimensional potential energy surfaces obtained from highly correlated ab initio…
Figures and Tables from this paper
80 Citations
The rotational excitation of HCN and HNC by He: temperature dependence of the collisional rate coefficients
- Physics
- 2010
Modelling of molecular emission from interstellar clouds requires the calculation of rates for excitation by collisions with the most abundant species. This paper deals with the calculation of rate…
Hyperfine excitation of HCN by H2 at low temperature
- Physics
- 2012
Modelling of molecular emission spectra from interstellar clouds requires the calculation of rate coefficients for (de-)excitation by collisions with the most abundant species. We calculate rate…
Collisional excitation of interstellar HCl by He
- Physics
- 2012
Modelling of molecular emission from interstellar clouds requires the calculation of rate coefficients for excitation by collisions with the most abundant species. This paper deals with the…
The Photodissociation of HCN and HNC: Effects on the HNC/HCN Abundance Ratio in the Interstellar Medium.
- PhysicsThe Astrophysical journal
- 2017
To properly describe the HNC/HCN abundance ratio in astronomical environments illuminated by an intense ultraviolet radiation field it is necessary to use different photodissociation rates for each of the two isomers, obtained by integrating the product of the photodISSociation cross sections and ultraviolet Radiation field over the relevant wavelength range.
The rotational excitation of the interstellar HNC by para- and ortho-H2.
- Physics, ChemistryPhysical chemistry chemical physics : PCCP
- 2011
A new four dimensional (4D) potential energy surface for the HNC-H(2) collisional system is presented and it is expected that they will help to solve the interstellar problem of relative abundance of the HCN and HNC isomers.
Rotational (de-)excitation of isocyanogen by collision with helium at low energies.
- PhysicsThe Journal of chemical physics
- 2018
The cross sections for the rotational (de-)excitation of CNCN after a collision by He up to 2000 cm-1 total energies are obtained and these cross sections are used to deduce the collision rates in the 10-300 K range.
Collisional excitation of HNC by He found to be stronger than for structural isomer HCN in experiments at the low temperatures of interstellar space
- PhysicsNature Chemistry
- 2022
HCN and its unstable isomer HNC are widely observed throughout the interstellar medium, with the HNC/HCN abundance ratio correlating strongly with temperature. In very cold environments HNC can even…
Rotational excitation of HCN by para- and ortho-H₂.
- PhysicsThe Journal of chemical physics
- 2014
New rate coefficients will be crucial to improve the estimation of the HCN abundance in the interstellar medium and were compared with previously published HCN-para-H2(j = 0) rate coefficients.
Isomerism Effects in the Collisional Excitation of Cyanoacetylene by Molecular Hydrogen
- Physics, ChemistryACS Earth and Space Chemistry
- 2019
Rotational excitation of the interstellar HC2NC and HNC3 molecules, two isomers of HC3N, induced by collisions with H2 is investigated at low collision energy using a quantum time-independent…
Revised study of the collisional excitation of HCO+ by H2(j = 0)
- Chemistry, Physics
- 2014
Rotational excitation of the interstellar HCO + by para-H 2 ( j = 0) is investigated. The scattering calculations are based on a new potential energy surface (PES) for the HCO + –H 2 van der Waals…
References
SHOWING 1-10 OF 46 REFERENCES
Rotational excitation of HC3N by H2 and He at low temperatures
- Physics, Chemistry
- 2007
Aims. Rates for rotational excitation of HC3N by collisions with He atoms and H2 molecules are computed for kinetic temperatures in the range 5−20 K and 5−100 K, respectively. Methods. These rates…
Electron-impact rotational and hyperfine excitation of HCN, HNC, DCN and DNC
- Physics
- 2007
Rotational excitation of isotopologues of HCN and HNC by thermal electron-impact is studied using the molecular R-matrix method combined with the adiabatic-nuclei-rotation approximation. Rate…
Rotational excitation of HCN by collisions
- Physics
- 1974
Rate constants for the rotational excitation of HCN by collisions with He atoms at temperatures below 100 K were computed from first principles and are presented in tabular form. The potential energy…
The rotational excitation of SiS by para- and ortho-H2
- Physics
- 2008
Over the next few years, the Atacama Large Millimeter Array (ALMA) and Herschel missions will perform high spatial and spectral resolution studies at infrared and submillimetre wavelengths. Modelling…
Rotationally inelastic collisions of SO(X3Sigma-) with H2: potential energy surface and rate coefficients for excitation by para-H2 at low temperature.
- PhysicsThe Journal of chemical physics
- 2007
The authors present a new four-dimensional potential energy surface for the SO-H2 system, calculated at an internuclear SO distance frozen at its experimental minimum energy distance, obtained at the RCCSD(T) level using the aug-cc-pVTZ basis sets for the four atoms.
Ro-vibrational excitation of SiS by He
- Physics, Chemistry
- 2007
Modelling of the astrophysical spectra requires accurate radiative and collisional rates for species of astrophysical interest. The present paper focuses on the calculation of ro-vibrational…
Quantum scattering of SiS with H2: potential energy surface and rate coefficients at low temperature.
- Physics, ChemistryThe Journal of chemical physics
- 2008
A new four dimensional potential energy surface for the SiS-H2 system is presented and perturbational components of the interaction energy are calculated using symmetry-adapted perturbation theory approach to explain the anisotropy of the potentialEnergy surface.
Improved low-temperature rate constants for rotational excitation of CO by H 2
- Physics, Chemistry
- 2006
Cross sections for the rotational (de)excitation of CO by ground state para- and ortho-H 2 are obtained using quantum scattering calculations for collision energies between 1 and 520 cm -1 . A new…
Calculations on the rates, mechanisms, and interstellar importance of the reactions between C and NH2 and between N and CH2
- Physics
- 2000
The attempt to understand the temperature dependence of the HNC/HCN abundance ratio in interstellar clouds has been long standing and indecisive. In this paper we report quantum chemical and…
Theoretical study of the He-HCN, Ne-HCN, Ar-HCN, and Kr-HCN complexes
- Chemistry
- 2001
The two-dimensional potential energy surfaces for the He–HCN, Ne–HCN, Ar–HCN, and Kr–HCN complexes are presented. Calculations have been performed using single and double excitation coupled-cluster…