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Ring-Polymer Molecular Dynamics for the Prediction of Low-Temperature Rates: An Investigation of the C(1D) + H2 Reaction
journal contribution
posted on 2015-12-17, 10:31 authored by Kevin M. Hickson, Jean-Christophe Loison, Hua Guo, Yury V. SuleimanovQuantum mechanical calculations are
important tools for predicting
the rates of elementary reactions, particularly for those involving
hydrogen and at low temperatures where quantum effects become increasingly
important. These approaches are computationally expensive, however,
particularly when applied to complex polyatomic systems or processes
characterized by deep potential wells. While several approximate techniques
exist, many of these have issues with reliability. The ring-polymer
molecular dynamics method was recently proposed as an accurate and
efficient alternative. Here, we test this technique at low temperatures
(300–50 K) by analyzing the behavior of the barrierless C(1D) + H2 reaction over the two lowest singlet potential
energy surfaces. To validate the theory, rate coefficients were measured
using a supersonic flow reactor down to 50 K. The experimental and
theoretical rates are in excellent agreement, supporting the future
application of this method for determining the kinetics and dynamics
of a wide range of low-temperature reactions.