scholarly journals The low temperature D+ + H2 → HD + H+ reaction rate coefficient: a ring polymer molecular dynamics and quasi-classical trajectory study

2018 ◽  
Vol 20 (41) ◽  
pp. 26752-26763 ◽  
Author(s):  
Somnath Bhowmick ◽  
Duncan Bossion ◽  
Yohann Scribano ◽  
Yury V. Suleimanov
Keyword(s):  
Molecular Dynamics ◽  
Low Temperature ◽  
Low Temperatures ◽  
Reaction Rate ◽  
Rate Coefficient ◽  
Classical Trajectory ◽  
Reaction Rate Coefficient ◽  
Ring Polymer ◽  
Ring Polymer Molecular Dynamics ◽  
Trajectory Methods

The D+ + H2 → HD + H+ reaction rate coefficient has been calculated at low temperatures (20–100 K) by ring polymer molecular dynamics and quasi-classical trajectory methods.

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.

Photoexcited Ag ejection from a low-temperature He cluster: a simulation study by nonadiabatic Ehrenfest ring-polymer molecular dynamics

2017 ◽  
Vol 19 (21) ◽  
pp. 13798-13806 ◽  
Author(s):  
Yusuke Seki ◽  
Toshiyuki Takayanagi ◽  
Motoyuki Shiga
Keyword(s):  
Molecular Dynamics ◽  
Low Temperature ◽  
Molecular Dynamics Simulations ◽  
Simulation Study ◽  
Ring Polymer ◽  
Cluster A ◽  
Ring Polymer Molecular Dynamics ◽  
Dynamics Simulations

Nonadiabatic ring-polymer molecular dynamics simulations were performed to understand the photoexcitation dynamics of a low-temperature Ag·He500 cluster.

scholarly journals An experimental and theoretical investigation of the C(1D) + D2 reaction

2017 ◽  
Vol 19 (1) ◽  
pp. 480-486 ◽  
Author(s):  
Kevin M. Hickson ◽  
Yury V. Suleimanov
Keyword(s):  
Molecular Dynamics ◽  
Low Temperature ◽  
Theoretical Investigation ◽  
Rate Constants ◽  
Molecular Dynamics Calculations ◽  
P Rate ◽  
Ring Polymer ◽  
Ring Polymer Molecular Dynamics

Rate constants derived from ring polymer molecular dynamics calculations confirm the validity of this method for studying low-temperature complex-forming reactions

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