Sodium isocyanide–Helium potential energy surface and astrophysical applications

Gharbi, C; Ajili, Y.; Abdallah, D. Ben; Hochlaf, M.

doi:10.1007/s00214-020-02704-x

Cited by 1 publication

(1 citation statement)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For CH 3 CN−He, the dominant term is V 20 , a term responsible for transitions involving |Δj| = 2, hence, the largest cross sections are obtained for even Δj transitions. Such results were already observed for other systems: Propensity rules which favor |Δj| = 2 were also found for X-CN systems such as SiH 3 CN, 41 HCN, 42 and CCN 43 and which favor |Δj| = 1 for X-NC complex such as HMgNC, 44 HNC, 42 and NaNC 45 as well as MgNC and AlNC. 46 Recently, collisions of HCN− He and HNC−He were investigated experimentally with chirped pulse in uniform supersonic flow technique by Hays et al 47 Good agreement between the scattering calculations and experimental measurements was found, and similar effects of propensity rules were observed for collisions of HCN and HNC with He atoms.…”

Section: Cross Section Computationssupporting

confidence: 73%

Interaction of CH₃CN and CH₃NC with He: Potential Energy Surfaces and Low-Energy Scattering

2022

View full text Add to dashboard Cite

Several nitrogen-bearing molecules, such as methyl cyanide (or acetonitrile, CH3CN) and methyl isocyanide (CH3NC) of interest here, have been observed in various astrophysical environments. The accurate modeling of their abundance requires the calculation of rate coefficients for their collisional excitation with species such as He atoms or H2 molecules at low temperatures. In this work we compute new three-dimensional potential energy surfaces for the CH3NC–He and CH3CN–He van der Waals complexes by means of the explicitly correlated coupled cluster approach with single, double and perturbative triple excitation CCSD(T)/F12a in conjunction with the aug-cc-pVTZ basis set. We find a global minimum with D e = 55.10 and 58.61 cm–1 for CH3CN–He and CH3NC–He, respectively, while the dissociation energy D 0 of the complexes are 18.64 and 18.65 cm–1, respectively. Low-energy scattering calculations of pure rotational (de-)excitation of CH3CN and CH3NC by collision with He atoms are carried out with the close-coupling method, and the collisional cross sections of ortho- and para-CH3NC and CH3CN are computed for kinetic energies up to 100 cm–1. While the PESs for both complexes are qualitatively similar, that of CH3NC–He is more anisotropic, leading to different propensity rules for rotational excitation. For CH3NC–He, we find that |Δj| = 1 transitions are dominant at low kinetic energy and a propensity rule that favors odd Δj transitions is observed, whereas for CH3CN the dominant cross sections are associated with transitions with |Δj| = 2. We expect that the findings of this study will be beneficial for astrophysical investigations as well as laboratory experiments.

show abstract

Section: Cross Section Computationssupporting

confidence: 73%

Interaction of CH₃CN and CH₃NC with He: Potential Energy Surfaces and Low-Energy Scattering

2022

View full text Add to dashboard Cite

show abstract

Sodium isocyanide–Helium potential energy surface and astrophysical applications

Cited by 1 publication

References 48 publications

Interaction of CH₃CN and CH₃NC with He: Potential Energy Surfaces and Low-Energy Scattering

Interaction of CH₃CN and CH₃NC with He: Potential Energy Surfaces and Low-Energy Scattering

Contact Info

Product

Resources

About

Sodium isocyanide–Helium potential energy surface and astrophysical applications

Cited by 1 publication

References 48 publications

Interaction of CH3CN and CH3NC with He: Potential Energy Surfaces and Low-Energy Scattering

Interaction of CH3CN and CH3NC with He: Potential Energy Surfaces and Low-Energy Scattering

Contact Info

Product

Resources

About

Interaction of CH₃CN and CH₃NC with He: Potential Energy Surfaces and Low-Energy Scattering

Interaction of CH₃CN and CH₃NC with He: Potential Energy Surfaces and Low-Energy Scattering