Low Temperature Kinetics of the Reaction Between Methanol and the CN Radical

Gupta, Divita; Ely, Sidaty Cheikh Sid; Cooke, Ilsa R.; Guillaume, Théo; Khedaoui, Omar Abdelkader; Hearne, Thomas; Hays, Brian M.; Sims, Ian

doi:10.1021/acs.jpca.9b08472

Cited by 10 publications

(11 citation statements)

References 77 publications

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“…A Controlled Evaporation and Mixing system was used to introduce benzene into the flow (Bronkhorst CEM, described in detail in Gupta et al (2019)). The system consists of a Coriolis liquid flow meter (Bronkhorst mini CORI-FLOW ML120V00) that introduces a metered flow of liquid benzene into an evaporator (Bronkhorst W-202A-222-K), followed by controlled dilution with a buffer gas via a thermal mass flow controller (Bronkhorst EL-FLOW Prestige).…”

Section: Methodsmentioning

confidence: 99%

Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆

Cooke

Gupta

Messinger

et al. 2020

ApJL

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Section: Methodsmentioning

confidence: 99%

Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆

Cooke

Gupta

Messinger

et al. 2020

ApJL

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“…Rate constants were determined using the PLP–LIF technique. Temperatures down to 15 K were achieved using the CRESU technique ( Cinétique de Réaction en Ecoulement Supersonique Uniforme ; reaction kinetics in uniform supersonic flow), which has been described in detail previously. ,, Briefly, toluene (Sigma-Aldrich, 99.9%) was introduced into the gas flow with a Controlled Evaporation and Mixing system (Bronkhorst CEM), as described in Gupta et al The toluene and ICN (Acros Organics, 98%), used as the CN precursor, were mixed in a buffer gas of He (99.995%, Air Liquide), Ar (99.998%, Air Liquide), or N 2 (99.995%, Air Liquide), depending on the desired CRESU conditions. Concentrations of toluene and ICN were kept ≲0.1% of the total density in order not to affect the uniformity of the gas flow.…”

Section: Methodsmentioning

confidence: 99%

Rate Constants of the CN + Toluene Reaction from 15 to 294 K and Interstellar Implications

et al. 2020

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CN is known for its fast reactions with hydrocarbons at low temperatures, but relatively few studies have focused on the reactions between CN and aromatic molecules. The recent detection of benzonitrile in the interstellar medium, believed to be produced by the reaction of CN and benzene, has ignited interest in studying these reactions. Here, we report rate constants of the CN + toluene (C 7 H 8) reaction between 15 and 294 K using a CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme; reaction kinetics in uniform supersonic flow) apparatus coupled with the pulsed laser photolysis-laser induced fluorescence (PLP-LIF) technique. We also present the stationary points on the potential energy surface of this reaction to study the available reaction pathways. We find the rate constant does not change over this temperature range, with an average value of (4.1 ± 0.2) × 10-10 cm 3 s-1 , which is notably faster than the only previous measurement at 105 K. While the reason for this disagreement is unknown, we discuss the possibility that it is related to enhanced multiphoton effects in the previous work.

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“…For the CRESU experiments a flow of liquid vinyl cyanide set by a Coriolis flow meter (Bronkhorst mini CORI-FLOW ML120 V00) to 5 g h -1 was vaporized through a controlled evaporative mixer (CEM -Bronkhorst W-202A-222-K) with the vapor transported by a flow of 5 SLM (standard liters per minute) of a helium carrier gas supplied by a separate mass flow controller (Bronkhorst EL-FLOW Prestige). 31 The evaporated mixture was injected along with an additional supply of helium buffer gas, which was continuously adjusted to maintain a constant pressure of 97.73 mbar, as measured by a capacitance This is the author's peer reviewed, accepted manuscript. However, the online version of record will be different from this version once it has been copyedited and typeset.…”

Section: B Gas-phase Studiesmentioning

confidence: 99%

A novel Ka-band chirped-pulse spectrometer used in the determination of pressure broadening coefficients of astrochemical molecules

Hearne

Khedaoui

Hays

et al. 2020

The Journal of Chemical Physics

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A novel chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer has been constructed to cover the for use in the CRESUCHIRP project, which aims to study the branching ratios of reactions at low temperatures using the chirped-pulse in uniform flow (CPUF) technique. The design takes advantage of recent developments in radio-frequency components; notably high-frequency, highpower solid-state amplifiers. The spectrometer had a flatness of 5.5 dB across the spectral range, produced harmonic signals below -20 dBc, and the recorded signal scaled well to 6 million averages. The new spectrometer was used to determine pressure broadening coefficients with a helium collider at room temperature for three molecules relevant to astrochemistry, applying the Voigt function to fit the magnitude of the Fourier-transformed data in the frequency domain. The pressure broadening coefficient for OCS was determined to be (2.45 ± 0.02) MHz mbar -1 at room temperature, which agreed well with previous measurements. Pressure broadening coefficients were also determined for multiple transitions of vinyl cyanide and benzonitrile. Additionally, the spectrometer was coupled with a cold, uniform flow from a Laval nozzle. The spectrum of vinyl cyanide was recorded in the flow, and its rotational temperature was determined to be (24 ± 11) K. This temperature agreed with a prediction of the composite temperature of the system through simulations of the experimental environment coupled with calculations of the solution to the optical Bloch equations. These results pave the way for future quantitative studies in low-temperature and high-pressure environments using CP-FTMW spectroscopy.

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Low Temperature Kinetics of the Reaction Between Methanol and the CN Radical

Cited by 10 publications

References 77 publications

Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆

Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆

Rate Constants of the CN + Toluene Reaction from 15 to 294 K and Interstellar Implications

A novel Ka-band chirped-pulse spectrometer used in the determination of pressure broadening coefficients of astrochemical molecules

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Low Temperature Kinetics of the Reaction Between Methanol and the CN Radical

Cited by 10 publications

References 77 publications

Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C6H6

Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C6H6

Rate Constants of the CN + Toluene Reaction from 15 to 294 K and Interstellar Implications

A novel Ka-band chirped-pulse spectrometer used in the determination of pressure broadening coefficients of astrochemical molecules

Contact Info

Product

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Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆

Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆