Isomer-Specific Mass Spectrometric Detection Via “Semisoft” Strong-Field Ionization

Yan, Lu; Cudry, Fadia; Li, Wen; Suits, Arthur G.

doi:10.1021/jp403118c

Cited by 6 publications

(6 citation statements)

References 37 publications

(46 reference statements)

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“…Near-infrared femtosecond laser pulse can be used to selectively ionize isomers through strong field ionization. 47,48 The laser dependence of the ion signal as well as the fragmentation patterns can be used to identify isomers from complex mixtures. Recent experiments have also demonstrated the ability of chirped-pulse millimeter-wave spectroscopy to identify radicals and closed shell molecules in pyrolysis environments.…”

Section: Introductionmentioning

confidence: 99%

Insights into gas-phase reaction mechanisms of small carbon radicals using isomer-resolved product detection

Trevitt

Goulay

2016

Phys. Chem. Chem. Phys.

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For reactive gas-phase environments, including combustion, extraterrestrials atmospheres and our Earth's atmosphere, the availability of quality chemical data is essential for predictive chemical models. These data include reaction rate coefficients and product branching fractions. This perspective overviews recent isomerresolved production detection experiments for reactions of two of the most reactive gas phase radicals, the CN and CH radicals, with a suite of small hydrocarbons. A particular focus is given to flow-tube experiments using synchrotron photoionization mass spectrometry. Coupled with computational studies and other experiment techniques, flow tube isomer-resolved product detection have provided significant mechanistic details of these radical + neutral reactions with some general patterns emerging. Disciplines Medicine and Health Sciences | Social and Behavioral Sciences ABSTRACTFor reactive gas-phase environments, including combustion, extraterrestrials atmospheres and our Earth's atmosphere, the availability of quality chemical data is essential for predictive chemical models. These data include reaction rate coefficients and product branching fractions. This perspective overviews recent isomer-resolved production detection experiments for reactions of two of the most reactive gas phase radicals, the CN and CH radicals, with a suite of small hydrocarbons. A particular focus is given to flowtube experiments using synchrotron photoionization mass spectrometry. Coupled with computational studies and other experiment techniques, flow tube isomer-resolved product detection have provided significant mechanistic details of these radical + neutral reactions with some general patterns emerging.

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Section: Introductionmentioning

confidence: 99%

Insights into gas-phase reaction mechanisms of small carbon radicals using isomer-resolved product detection

Trevitt

Goulay

2016

Phys. Chem. Chem. Phys.

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“…The availability of synchrotron beamline time must be considered as well. A promising alternative ionization method, strong-field ionization by femtosecond laser pulses, was recently demonstrated [27]. Although similar issues of photo-induced dissociation must be considered, the technique is conveniently lab-based.…”

Section: Introductionmentioning

confidence: 99%

Chirped-pulse millimeter-wave spectroscopy for dynamics and kinetics studies of pyrolysis reactions

Prozument

Park

Shaver

et al. 2014

Phys. Chem. Chem. Phys.

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A Chirped-Pulse millimeter-Wave (CPmmW) spectrometer is applied to the study of chemical reaction products that result from pyrolysis in a Chen nozzle heated to 1000-1800 K. Millimeter-wave rotational spectroscopy unambiguously determines, for each polar reaction product, the species, the conformers, relative concentrations, conversion percentage from precursor to each product, and, in some cases, vibrational state population distributions. A chirped-pulse spectrometer can, within the frequency range of a single chirp, sample spectral regions of up to ∼10 GHz and simultaneously detect many reaction products. Here we introduce a modification to the CPmmW technique in which multiple chirps of different spectral content are applied to a molecular beam pulse that contains the pyrolysis reaction products. This technique allows for controlled allocation of its sensitivity to specific molecular transitions and effectively doubles the bandwidth of the spectrometer. As an example, the pyrolysis reaction of ethyl nitrite, CH3CH2ONO, is studied, and CH3CHO, H2CO, and HNO products are simultaneously observed and quantified, exploiting the multi-chirp CPmmW technique. Rotational and vibrational temperatures of some product molecules are determined. Subsequent to supersonic expansion from the heated nozzle, acetaldehyde molecules display a rotational temperature of 4 ± 1 K. Vibrational temperatures are found to be controlled by the collisional cooling in the expansion, and to be both species- and vibrational mode-dependent. Rotational transitions of vibrationally excited formaldehyde in levels ν4, 2ν4, 3ν4, ν2, ν3, and ν6 are observed and effective vibrational temperatures for modes 2, 3, 4, and 6 are determined and discussed.

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“…This has motivated the use of tunable vacuum ultraviolet synchrotron radiation as a universal but selective detection technique that has been used with great success to identify reaction products in dynamics studies, in flames and pyrolysis, and for product identification in kinetics studies . We have recently shown that the modest fragmentation that occurs in strong-field ionization (SFI) of molecules with femtosecond nonresonant laser pulses may be used as a mass spectral fingerprint to identify and quantify stable molecules in mixtures . In the present study, we extend these investigations to radicals and pyrolytic reaction products and show that we can use the ion yield versus the logarithm of the laser intensity, much as the synchrotron studies use tunable photon energy to achieve isomer-selective detection and to achieve some insights into the ionization mechanism.…”

Section: Introductionmentioning

confidence: 71%

“…Weber and Zhang suggested that the pyrolysis product C 3 H 4 could be either allene, propyne, or quite possibly a mixture of the two, following the elimination of C 2 H 4 . We previously examined the SFI of propyne and allene . The results showed very distinct fragmentation behavior for these two molecules; propyne gave almost exclusively m / z = 40, while allene gave a dominant peak at m / z = 39.…”

Section: Results and Discussionmentioning

confidence: 99%

Strong-Field Ionization of Flash Pyrolysis Reaction Products

et al. 2015

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We report the coupling of a flash pyrolysis molecular beam source with nonresonant strong-field ionization in a time-of-flight mass spectrometer. The saturation laser intensities at which ionization occurs for the various product species are generally found to correlate closely with the ionization energies, as has been seen for closed-shell molecules. It is then possible to use this correlation to identify the product and quantify isomers from among several candidate species whose ionization energies are known. The approach is analogous to using tunable vacuum ultraviolet ionization to identify reaction products.

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Isomer-Specific Mass Spectrometric Detection Via “Semisoft” Strong-Field Ionization

Cited by 6 publications

References 37 publications

Insights into gas-phase reaction mechanisms of small carbon radicals using isomer-resolved product detection

Insights into gas-phase reaction mechanisms of small carbon radicals using isomer-resolved product detection

Chirped-pulse millimeter-wave spectroscopy for dynamics and kinetics studies of pyrolysis reactions

Strong-Field Ionization of Flash Pyrolysis Reaction Products

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