How Measurements of Rate Coefficients at Low Temperature Increase the Predictivity of Photochemical Models of Titan’s Atmosphere†

2009 ◽  
Vol 113 (42) ◽  
pp. 11227-11237 ◽  
Author(s):  
E. Hébrard ◽  
M. Dobrijevic ◽  
P. Pernot ◽  
N. Carrasco ◽  
A. Bergeat ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Increase ◽  
Rate Coefficients ◽  
Photochemical Models

scholarly journals On apparent barrier-free reactions

2020 ◽  
Vol 3 (1) ◽  
pp. 3-8
Author(s):  
Maikel Ballester
Keyword(s):  
Low Temperature ◽  
Chemical Reactions ◽  
Rate Constant ◽  
Kinetic Models ◽  
Rate Coefficient ◽  
Minimum Energy ◽  
Temperature Limit ◽  
Rate Coefficients ◽  
Minimum Energy Path ◽  
Full Dimension

Rate coefficients of bi-molecular chemical reactions are fundamental for kinetic models. The rate coefficient dependence on temperature is commonly extracted from the analyses of the reaction minimum energy path. However, a full dimension study of the same reaction may suggest a different asymptotic low-temperature limit in the rate constant than the obtained from the energetic profile.

Rotational cross sections and rate coefficients of CP ( X 2 Σ + ) $\mathrm{CP}(\mathrm{X}^{2}\varSigma ^{+})$ induced by its collision with He ( 1 S ) $\mathrm{He}(^{1}S)$ at low temperature

2018 ◽  
Vol 363 (3) ◽  
Author(s):  
Théophile Tchakoua ◽  
Mama Pamboundom ◽  
Berthelot Said Duvalier Ramlina Vamhindi ◽  
Serge Guy Nana Engo ◽  
Ousmanou Motapon ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cross Sections ◽  
Rate Coefficients

scholarly journals Experimental N V and Ne VIII low-temperature dielectronic recombination rate coefficients

2005 ◽  
Vol 437 (3) ◽  
pp. 1151-1157 ◽  
Author(s):  
S. Böhm ◽  
A. Müller ◽  
S. Schippers ◽  
W. Shi ◽  
M. Fogle ◽  
...  
Keyword(s):  
Low Temperature ◽  
Recombination Rate ◽  
Dielectronic Recombination ◽  
Rate Coefficients

scholarly journals Low temperature gas phase reaction rate coefficient measurements: Toward modeling of stellar winds and the interstellar medium

2019 ◽  
Vol 15 (S350) ◽  
pp. 382-383
Author(s):  
Niclas A. West ◽  
Edward Rutter ◽  
Mark A. Blitz ◽  
Leen Decin ◽  
Dwayne E. Heard
Keyword(s):  
Low Temperature ◽  
Interstellar Medium ◽  
Gas Phase ◽  
Low Temperatures ◽  
Reaction Rate ◽  
Rate Coefficient ◽  
Building Blocks ◽  
Rate Coefficients ◽  
Stellar Winds ◽  
Phase Reaction

AbstractStellar winds of Asymptotic Giant Branch (AGB) stars are responsible for the production of ∼85% of the gas molecules in the interstellar medium (ISM), and yet very few of the gas phase rate coefficients under the relevant conditions (10 – 3000 K) needed to model the rate of production and loss of these molecules in stellar winds have been experimentally measured. If measured at all, the value of the rate coefficient has often only been obtained at room temperature, with extrapolation to lower and higher temperatures using the Arrhenius equation. However, non-Arrhenius behavior has been observed often in the few measured rate coefficients at low temperatures. In previous reactions studied, theoretical simulations of the formation of long-lived pre-reaction complexes and quantum mechanical tunneling through the barrier to reaction have been utilized to fit these non-Arrhenius behaviours of rate coefficients.Reaction rate coefficients that were predicted to produce the largest change in the production/loss of Complex Organic Molecules (COMs) in stellar winds at low temperatures were selected from a sensitivity analysis. Here we present measurements of rate coefficients using a pulsed Laval nozzle apparatus with the Pump Laser Photolysis - Laser Induced Fluorescence (PLP-LIF) technique. Gas flow temperatures between 30 – 134 K have been produced by the University of Leeds apparatus through the controlled expansion of N2 or Ar gas through Laval nozzles of a range of Mach numbers between 2.49 and 4.25.Reactions of interest include those of OH, CN, and CH with volatile organic species, in particular formaldehyde, a molecule which has been detected in the ISM. Kinetics measurements of these reactions at low temperatures will be presented using the decay of the radical reagent. Since formaldehyde and the formal radical (HCO) are potential building blocks of COMs in the interstellar medium, low temperature reaction rate coefficients for their production and loss can help to predict the formation pathways of COMs observed in the interstellar medium.

Cross sections and low temperature rate coefficients for the H + CH+reaction: a quasiclassical trajectory study

2007 ◽  
Vol 9 (5) ◽  
pp. 582-590 ◽  
Author(s):  
Philippe Halvick ◽  
Thierry Stoecklin ◽  
Pascal Larrégaray ◽  
Laurent Bonnet
Keyword(s):  
Low Temperature ◽  
Cross Sections ◽  
Rate Coefficients ◽  
Temperature Rate

Observation of organosulfur products (thiovinoxy, thioketene and thioformyl) in crossed-beam experiments and low temperature rate coefficients for the reaction S(1D) + C2H4

2009 ◽  
Vol 11 (23) ◽  
pp. 4701 ◽  
Author(s):  
Francesca Leonori ◽  
Raffaele Petrucci ◽  
Nadia Balucani ◽  
Piergiorgio Casavecchia ◽  
Marzio Rosi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Rate Coefficients ◽  
Temperature Rate
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