Publications by authors named "B Desrousseaux"

Inelastic collisions and elementary chemical reactions proceeding through the formation and subsequent decay of an intermediate collision complex, with an associated deep well on the potential energy surface, pose a challenge for accurate fully quantum mechanical approaches, such as the close-coupling method. In this study, we report on the theoretical prediction of temperature-dependent state-to-state rate coefficients for these complex-mode processes, using a statistical quantum method. This statistical adiabatic channel model is benchmarked by a direct comparison using accurate rate coefficients from the literature for a number of systems (H + H, HD + H, SH + H, and CH + H) of interest in astrochemistry and astrophysics.

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In the early Universe, the cooling mechanisms of the gas significantly rely on the HD abundance and excitation conditions. A proper modeling of its formation and destruction paths as well as its excitation by both radiative and collisional processes is then required to accurately describe the cooling mechanisms of the pristine gas. In such media, ion-molecule reactions are dominant.

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Article Synopsis
  • The study investigates how collisions between hydrogen (H) and interstellar PN molecules cause rotational excitation.
  • A new four-dimensional potential energy surface (PES) for the PN-H system was created using advanced computational methods, revealing a linear structure with specific intermolecular distances and energy characteristics.
  • The findings include varying dissociation energies for different hydrogen forms and emphasize that the rotational excitation data will enhance the understanding of PN abundance in the interstellar medium.
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The HeH molecule is the first to be formed in the Universe. Its recent detection, in the interstellar medium, has increased the interest in the study of the physical and chemical properties of this ion. Here, we report exact quantum time-independent calculations of the collisional cross sections and rate coefficients for the rotational excitation of HeH by H.

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The CF molecule is considered one of the key species for the study of fluorine chemistry in the interstellar medium (ISM). Its recent detection, as well as its potential use as a tracer for atomic fluorine in the ISM, has increased the interest in the study of the physical and chemical properties of this cation. Accurate determination of the CF abundance in the ISM requires detailed modeling of its excitation from both radiation and collisions with the most dominant species, which are usually atomic and molecular hydrogen.

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