Rotational (de)-excitation of linear C<sub>3</sub>O by collision with He

Khadri, F.; Hammami, K.

doi:10.1039/c8cp07409g

Cited by 9 publications

(7 citation statements)

References 37 publications

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“…The so-obtained analytical potentials are shown in Fig. 1, they are identical to the interpolated ab initio PESs represented in the works of Khadri & Hammami (2019) and Khadri et al (2022). It is worth noting that in this representation the linear configurations He ) and present shallow minima.…”

Section: Analytical Fitmentioning

confidence: 77%

“…The data reported in this work are calculated using the potential energy surfaces (PESs) of the C 3 O-He and C 5 O-He complexes (Khadri & Hammami 2019;Khadri et al 2022). Briefly, the PESs are calculated at the CCSD(T)-F12 2 /aug-cc-pVTZ 3 level of theory using the rigid-rotor approximation.…”

Section: Analytical Fitmentioning

confidence: 99%

“…To obtain collisional rate coefficients for higher rotational levels of C 3 O and C 5 O, we determine new analytical fits of the ab initio potentials including few radial terms (𝑉 𝜆 ) to keep the computational time reasonably low. In fact, due to the rod-like shape of the C 𝑛 O molecules, Khadri & Hammami (2019) and Khadri et al (2022) used 77 and 72 terms to reproduce reasonably well the ab initio PESs of C 3 O and C 5 O, respectively. To reduce the number of radial terms without losing precision on the analytical potentials, we used 1 rotational quantum number of H 2 2 explicitly correlated coupled cluster approach with single, double and perturbative triple excitation 3 augmented-correlation consistent-polarised valence triple zeta Gaussian basis set (𝑏) stands for Khadri et al (2022).…”

Section: Analytical Fitmentioning

confidence: 99%

“…Collisional excitation of C 3 O (Khadri & Hammami 2019) and C 5 O (Khadri et al 2022) by He was studied recently by mean of state-ofthe-art methods. New 2D-PESs were calculated using high accurate ab initio level of theories.…”

Section: Introductionmentioning

confidence: 99%

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The effect of scattering calculations on non-LTE modelling of the C3O and C5O abundances in TMC-1

Bop

Khadri

Hammami

2022

Monthly Notices of the Royal Astronomical Society

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Tricarbon and pentacarbon monoxides have been detected towards TMC-1 with relatively important abundances. Understanding their chemical formation of these molecules requires interpreting their observational spectra by mean of non-local thermodynamical equilibrium modelling. For this purpose, we report rate coefficients of C3O and C5O induced by collision with He for temperatures up to 100 K. These data are obtained by calculating inelastic cross sections for the 31 low-lying rotational levels of C3O and C5O using the close-coupling approach. The comparison of the new rate coefficients with those of HC3N and HC5N, previously used to interpret the observational spectra of C3O and C5O, reveals differences of up to an order of magnitude. The effect of the new collisional rate coefficients in radiative transfer calculations is checked by computing the excitation temperatures for some transitions and simulating the C3O and C5O column densities observed towards TMC-1. Our findings suggest that the use of HCnN as template for CnO may lead to local thermodynamic equilibrium conditions for gas densities as low as ∼103 cm−3. Regarding the interpretation of the observational spectra, using radiative transfer modelling based on the actual CnO collisional rate coefficients instead of rotational diagram analysis leads to underestimate the column densities reported in the literature by up to 25% and accordingly the C3O/ C5O abundance ratio by up to 50%. We expect that the new rate coefficients and the radiative transfer calculations presented in this work will encourage further modellings of the CnO abundance and accordingly constrain the chemistry.

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Section: Analytical Fitmentioning

confidence: 77%

Section: Analytical Fitmentioning

confidence: 99%

Section: Analytical Fitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The effect of scattering calculations on non-LTE modelling of the C3O and C5O abundances in TMC-1

Bop

Khadri

Hammami

2022

Monthly Notices of the Royal Astronomical Society

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“…This leads us to think that, for very low temperatures, Fig. 6 Comparison of de-excitation rates (in cm 3 s −1 ) at 10 K (red dots) and 20 K (blue marks) for the C 3 S-He collision, this work vs. C 3 O-He (Khadri and Hammami 2019). A black continuous line shows the 1 : 1 ratio it is the large rotational levels that are more solicited, in a different way from the generally known trend.…”

Section: Rate Coefficientsmentioning

confidence: 99%

Rotational de-excitation of tricarbon monosulfide (C3S) in collision with (He): potential energy surface and rates

Sahnoun¹,

Khalifa²,

Khadri³

et al. 2020

Astrophys Space Sci

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Despite that the tricarbon monosulfide (C3S) is among the first sulfur-containing carbon-chain molecules to be detected in the interstellar medium, no studies focused on the determination of its collisional rates. These rate coefficients are essential to estimate the abundance of C3S in the interstellar medium. Computations of the C3S($^{1}\Sigma^{+}$ Σ + 1 ) downward rate coefficients, induced by collision with He, are performed by averaging the integral cross sections at low temperature (below $25~\text{K}$ 25 K ). Calculations of the cross sections in the close-coupling quantum time independent formalism for $E_{c}\leq110~\text{cm}^{-1}$ E c ≤ 110 cm − 1 and $J\leq10$ J ≤ 10 are based on a new 2-D potential energy surface. This PES is obtained from the explicit correlated coupled cluster with a single, double and perturbative triple excitation [ccsd(t)-f12] ab initio approach and the aug-cc-pVTZ basis sets. The PES have a global minimum of $-55.69~\text{cm}^{-1}$ − 55.69 cm − 1 located at $R=6.25$ R = 6.25 bohr and $\theta=94^{\circ}$ θ = 94 ∘ , and a second minimum of $-36.95~\text{cm}^{-1}$ − 36.95 cm − 1 at $R=9.35$ R = 9.35 bohr and $\theta=0^{\circ}$ θ = 0 ∘ . A comparison of C3S rates with those of the isoelectronic molecule C3O was made. The results indicate a great temperature dependence of the rates for transitions of $\Delta J>2$ Δ J > 2 . We expect that the new collisional data will allow for accurate determination of the C3S abundance in several interstellar regions.

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BASECOL2023 scientific content

Dubernet,

Boursier,

Denis-Alpizar

et al. 2024

A&A

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The global context of making numerous data produced by researchers available requires collecting and organising the data, assigning meaningful metadata, and presenting the data in a meaningful and homogeneous way. The BASECOL database, which collects inelastic rate coefficients for application to the interstellar medium and to circumstellar and cometary atmospheres, meets those requirements. We aim to present the scientific content of the BASECOL2023 edition. While the previous versions relied on finding rate coefficients in the literature, the current version is populated with published results sent by the producers of data. The paper presents the database, the type of data that can be found, the type of metadata that are used, and the Virtual Atomic and Molecular Data Centre (VAMDC) standards that are used for the metadata. Finally, we present the different datasets species by species. As the BASECOL database, interconnected with the VAMDC e-infrastructure, uses the VAMDC standards, the collisional data can be extracted with tools using VAMDC standards and can be associated with spectroscopic data extracted from other VAMDC connected databases such as the Cologne database for molecular spectroscopy (CDMS), the jet propulsion laboratory molecular spectroscopy database (JPL), and the high-resolution transmission molecular absorption database (HITRAN).

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Rotational (de)-excitation of linear C₃O by collision with He

Abstract: Calculation of the rate coefficients of C3O(1Σ+) induced by collision with He is performed for thermal temperatures below 25 K.

Cited by 9 publications

References 37 publications

The effect of scattering calculations on non-LTE modelling of the C3O and C5O abundances in TMC-1

The effect of scattering calculations on non-LTE modelling of the C3O and C5O abundances in TMC-1

Rotational de-excitation of tricarbon monosulfide (C3S) in collision with (He): potential energy surface and rates

BASECOL2023 scientific content

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Rotational (de)-excitation of linear C3O by collision with He

Abstract: Calculation of the rate coefficients of C3O(1Σ+) induced by collision with He is performed for thermal temperatures below 25 K.

Cited by 9 publications

References 37 publications

The effect of scattering calculations on non-LTE modelling of the C3O and C5O abundances in TMC-1

The effect of scattering calculations on non-LTE modelling of the C3O and C5O abundances in TMC-1

Rotational de-excitation of tricarbon monosulfide (C3S) in collision with (He): potential energy surface and rates

BASECOL2023 scientific content

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Rotational (de)-excitation of linear C₃O by collision with He