Detection of PLP Structure for Accurate Determination of Propagation Rate Coefficients over an Enhanced Range of PLP-SEC Conditions

2018 ◽  
Vol 52 (1) ◽  
pp. 55-71 ◽  
Author(s):  
Anatoly N. Nikitin ◽  
Igor Lacık ◽  
Robin A. Hutchinson ◽  
Michael Buback ◽  
Gregory T. Russell
Keyword(s):  
Accurate Determination ◽  
Propagation Rate ◽  
Rate Coefficients

Collisional excitation of the formyl radical (HCO) by molecular hydrogen

2020 ◽  
Vol 498 (4) ◽  
pp. 5361-5366
Author(s):  
Paul J Dagdigian
Keyword(s):  
Accurate Determination ◽  
Radiative Transition ◽  
Rate Coefficients ◽  
Cluster Method ◽  
Quantum Scattering ◽  
Close Coupling ◽  
Explicitly Correlated ◽  
Radiative Transition Rate ◽  
Fine And Hyperfine Structure

ABSTRACT This paper addresses the need for accurate rate coefficients for transitions between fine- and hyperfine-structure resolved rotational transitions in the formyl (HCO) radical induced by collisions with the two nuclear spin modifications of H2, the dominant molecule in the interstellar medium (ISM). These rate coefficients, as well as radiative transition rate coefficients, are required for accurate determination of the abundance of HCO in the ISM. Time-independent close-coupling quantum scattering calculations have been used to compute rate coefficients for (de-)excitation of HCO in collisions with para- and ortho-H2. These calculations utilized a potential energy surface for the interaction of HCO with H2 recently computed by the explicitly correlated RCCSD(T)-F12a coupled-cluster method. Rate coefficients for temperatures ranging from 5 to 400 K were calculated for all transitions among the fine and hyperfine levels associated with the first 22 rotational levels of HCO, whose energies are less than or equal to 144 K.

Determination of Free-Radical Propagation Rate Coefficients for Cycloalkyl and Functional Methacrylates by Pulsed-Laser Polymerization

1998 ◽  
Vol 31 (5) ◽  
pp. 1542-1547 ◽  
Author(s):  
R. A. Hutchinson ◽  
S. Beuermann ◽  
D. A. Paquet ◽  
J. H. McMinn ◽  
C. Jackson
Keyword(s):  
Free Radical ◽  
Pulsed Laser ◽  
Propagation Rate ◽  
Rate Coefficients ◽  
Radical Propagation ◽  
Pulsed Laser Polymerization

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

2020 ◽  
Vol 365 (12) ◽  
Author(s):  
E. Sahnoun ◽  
M. Ben Khalifa ◽  
F. Khadri ◽  
K. Hammami
Keyword(s):  
Potential Energy ◽  
Interstellar Medium ◽  
Potential Energy Surface ◽  
Cross Sections ◽  
Energy Surface ◽  
Accurate Determination ◽  
Carbon Chain ◽  
Basis Sets ◽  
Rate Coefficients

AbstractDespite 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.

Determination of Propagation Rate Coefficients for Methyl and 2-Ethylhexyl Acrylate via High Frequency PLP−SEC under Consideration of the Impact of Chain Branching

2010 ◽  
Vol 43 (24) ◽  
pp. 10427-10434 ◽  
Author(s):  
Tanja Junkers ◽  
Maria Schneider-Baumann ◽  
Sandy S. P. Koo ◽  
Patrice Castignolles ◽  
Christopher Barner-Kowollik
Keyword(s):  
High Frequency ◽  
Propagation Rate ◽  
Rate Coefficients ◽  
Chain Branching ◽  
The Impact
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