Determination of Kinetic Parameters in Laminar Flow Reactors. I. Theoretical Aspects

Carraro, Thomas; Heuveline, Vincent; Rannacher, Rolf

doi:10.1007/978-3-540-28396-6_9

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…2), taken to be the averaged value mentioned earlier, from several self-consistent measurements in the 1970s, λ C = 0.145 ± 0.015 μs −1 (at 50 bar). This also agrees well with a much more recently reported value [61]. Nevertheless, the fact remains that there is a considerable level of disagreement in published values for this rate.…”

Section: Musupporting

confidence: 92%

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H₂{1} reaction rate at 300 K

Bakule

Sukhorukov

Ishida

et al. 2015

J. Phys. B: At. Mol. Opt. Phys.

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This paper reports on the experimental background and methodology leading to recent results on the first accurate measurement of the reaction rate of the muonium (Mu) atom from a state-selected reactant in the gas phase: the Mu + H2 MuH + H reaction at 300 K, and its comparison with rigorous quantum rate theory, Bakule et al (2012 J. Phys. Chem. Lett. 3 2755). Stimulated Raman pumping, induced by 532 nm light from the 2nd harmonic of a Nd:YAG laser, was used to produce H2 in its first vibrational (v = 1) state, H , in a single Raman/reaction cell. A pulsed muon beam (from ‘ISIS’, at 50 Hz) matched the 25 Hz repetition rate of the laser, allowing data taking in equal ‘Laser-On/Laser-Off’ modes of operation. The signal to noise was improved by over an order of magnitude in comparison with an earlier proof-of-principle experiment. The success of the present experiment also relied on optimizing the overlap of the laser profile with the extended stopping distribution of the muon beam at 50 bar H2 pressure, in which Monte Carlo simulations played a central role. The rate constant, found from the analysis of three separate measurements, which includes a correction for the loss of concentration due to collisional relaxation with unpumped H2 during the time of each measurement, is = 9.9[(−1.4)(+1.7)] × 10−13 cm3 s−1 at 300 K. This is in good to excellent agreement with rigorous quantum rate calculations on the complete configuration interaction/Born–Huang surface, as reported earlier by Bakule et al, and which are also briefly commented on herein.

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Section: Musupporting

confidence: 92%

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H₂{1} reaction rate at 300 K

Bakule

Sukhorukov

Ishida

et al. 2015

J. Phys. B: At. Mol. Opt. Phys.

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“…These values, along with λ b , were determined from a fit to the laser-off data (Figure , top) and then fixed in fitting S ( t ). The collisional relaxation rate λ C was fixed at 0.145 μs –1 at 50 bar, from an average of several measurements ,− (uncertainty ±0.015 μs –1 ). The parameter f accounts for the overlap between the laser profile (region of pumped H 2 ) and the muon stopping distribution and was determined independently by integrating this overlap.…”

mentioning

confidence: 99%

State-Selected Reaction of Muonium with Vibrationally Excited H₂

Bakule

Fleming

Sukhorukov

et al. 2012

J. Phys. Chem. Lett.

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We report a new advance in the study of muonium (Mu) reactivity; specifically, we report the rate constant for the Mu + H2(vibrational quantum number n = 1) reaction determined by measurements at 300 K and by converged quantum mechanical calculations. Comparisons are made with earlier results for D + H2 (n = 1) and with the corresponding thermal reaction rates. The measurements are a sensitive probe of the high-curvature region in the entrance valley of the potential energy surface (PES) and thus provide a qualitatively different probe of the PES than that provided by any previous experiment.

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“…It becomes an estimation after substituting the unknown continuous solutions with computable quantities. As shown in several applications [9,30,29,26,10,5] one efficient method to produce computable quantities is the use of a patch-wise higher-order approximation of the terms z h and w h . In particular, we have used the following interpolation operator with…”

Section: A Posteriori Error Estimatorsmentioning

confidence: 99%

An Adaptive Newton Algorithm for Optimal Control Problems with Application to Optimal Electrode Design

Carraro

Dörsam

Frei

et al. 2018

J Optim Theory Appl

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In this work we present an adaptive Newton-type method to solve nonlinear constrained optimization problems in which the constraint is a system of partial differential equations discretized by the finite element method. The adaptive strategy is based on a goal-oriented a posteriori error estimation for the discretization and for the iteration error. The iteration error stems from an inexact solution of the nonlinear system of first order optimality conditions by the Newton-type method. This strategy allows to balance the two errors and to derive effective stopping criteria for the Newton-iterations. The algorithm proceeds with the search of the optimal point on coarse grids which are refined only if the discretization error becomes dominant. Using computable error indicators the mesh is refined locally leading to a highly efficient solution process. The performance of the algorithm is shown with several examples and in particular with an application in the neurosciences: the optimal electrode design for the study of neuronal networks.

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Determination of Kinetic Parameters in Laminar Flow Reactors. I. Theoretical Aspects

Cited by 5 publications

References 20 publications

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H₂{1} reaction rate at 300 K

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H₂{1} reaction rate at 300 K

State-Selected Reaction of Muonium with Vibrationally Excited H₂

An Adaptive Newton Algorithm for Optimal Control Problems with Application to Optimal Electrode Design

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Determination of Kinetic Parameters in Laminar Flow Reactors. I. Theoretical Aspects

Cited by 5 publications

References 20 publications

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H2{1} reaction rate at 300 K

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H2{1} reaction rate at 300 K

State-Selected Reaction of Muonium with Vibrationally Excited H2

An Adaptive Newton Algorithm for Optimal Control Problems with Application to Optimal Electrode Design

Contact Info

Product

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First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H₂{1} reaction rate at 300 K

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H₂{1} reaction rate at 300 K

State-Selected Reaction of Muonium with Vibrationally Excited H₂