How to Compute Electron Ionization Mass Spectra from First Principles

Bauer, Christoph; Grimme, Stefan

doi:10.1021/acs.jpca.6b02907

Cited by 107 publications

(125 citation statements)

References 127 publications

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“…We conclude with the more general notion that it has been very challenging to understand EI mass spectra of organic molecules, let alone to predict them from first principles. [64] The ability to record IR spectra for mass-selected fragment ions provides an elegant way to increase our understanding of the electron ionization of organic molecules. The ions produced in the dissociation of adamantane are commonly detected EI products of alkylbenzenes, which have been widely discussed in physical-organic mass spectrometry studies.…”

Section: Discussionmentioning

confidence: 67%

“…[64] The ability to record IR spectra for mass-selected fragment ions provides an elegant way to increase our understanding of the electron ionization of organic molecules. [64] The ability to record IR spectra for mass-selected fragment ions provides an elegant way to increase our understanding of the electron ionization of organic molecules.…”

Section: Discussionmentioning

confidence: 99%

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Spectroscopic Characterization of the Product Ions Formed by Electron Ionization of Adamantane

Bouwman

Horst

2018

ChemPhysChem

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A structural characterization of the products formed in the dissociative electron ionization of adamantane (C 10 H 16 ) is presented. Molecular structures of product ions are suggested based on multiple‐photon dissociation spectroscopy using the Free Electron Laser for Infrared eXperiments (FELIX) in combination with quantum‐chemical calculations. Product ions are individually isolated in an ion trap tandem mass spectrometer and their action IR spectra are recorded. Atomic hydrogen loss from adamantane yields the 1‐adamantyl isomer. The IR spectrum of the C 8 H 11 + product ion is best reproduced by computed spectra of 2‐ and 4‐protonated meta ‐xylene and ortho ‐ and para‐ protonated ethylbenzenes. The spectrum of the product ion at m/z 93 suggests that it is composed of a mixture of ortho ‐protonated toluene, para ‐protonated toluene and 1,2‐dihydrotropylium, while the spectrum of the m/z 79 ion is consistent with the benzenium ion. This study thus suggests that adamantane is efficiently converted into aromatic species and astrophysical implications for the interstellar medium are highlighted.

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Section: Discussionmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Spectroscopic Characterization of the Product Ions Formed by Electron Ionization of Adamantane

Bouwman

Horst

2018

ChemPhysChem

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“…So far only electron ionization mass spectra can be modeled with good accuracy. [73][74][75] The jump to the creation of in silico ESI-MS/MS spectra will require a substantial innovative and intellectual input from the quantum chemical community, mostly due to the variability of lowenergy CID spectra and the required fragmentation voltage spreads.…”

Section: Data-independent Acquisition Methodsmentioning

confidence: 99%

“…The development of quantum chemistry based methods for in silico generation of CID‐MS/MS mass spectra will be one of the next grand challenges in computational mass spectrometry. So far only electron ionization mass spectra can be modeled with good accuracy . The jump to the creation of in silico ESI‐MS/MS spectra will require a substantial innovative and intellectual input from the quantum chemical community, mostly due to the variability of low‐energy CID spectra and the required fragmentation voltage spreads.…”

Section: Creation Of Ms/ms Databasesmentioning

confidence: 99%

Identification of small molecules using accurate mass MS/MS search

Kind

Tsugawa

Čajka

et al. 2017

Mass Spectrometry Reviews

356

325

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Tandem mass spectral library search (MS/MS) is the fastest way to correctly annotate MS/MS spectra from screening small molecules in fields such as environmental analysis, drug screening, lipid analysis, and metabolomics. The confidence in MS/MS-based annotation of chemical structures is impacted by instrumental settings and requirements, data acquisition modes including data-dependent and data-independent methods, library scoring algorithms, as well as post-curation steps. We critically discuss parameters that influence search results, such as mass accuracy, precursor ion isolation width, intensity thresholds, centroiding algorithms, and acquisition speed. A range of publicly and commercially available MS/MS databases such as NIST, MassBank, MoNA, LipidBlast, Wiley MSforID, and METLIN are surveyed. In addition, software tools including NIST MS Search, MS-DIAL, Mass Frontier, SmileMS, Mass++, and XCMS to perform fast MS/MS search are discussed. MS/MS scoring algorithms and challenges during compound annotation are reviewed. Advanced methods such as the in silico generation of tandem mass spectra using quantum chemistry and machine learning methods are covered. Community efforts for curation and sharing of tandem mass spectra that will allow for faster distribution of scientific discoveries are discussed.

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“…Furthermore, single‐photon dissociative ionization data employing parent‐ion internal energy selection are not available. However, such data can be used to quantify bond dissociation energies on the cationic surface accurately, and provide details on the underlying dissociation mechanism, relevant for understanding and modeling, for example, mass spectra …”

Section: Introductionmentioning

confidence: 99%

Dissociative Ionization and Thermal Decomposition of Cyclopentanone

Pastoors

Bodi

Hemberger

et al. 2017

Chemistry A European J

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Despite the growing use of renewable and sustainable biofuels in transportation, their combustion chemistry is poorly understood, limiting our efforts to reduce harmful emissions. Here we report on the (dissociative) ionization and the thermal decomposition mechanism of cyclopentanone, studied using imaging photoelectron photoion coincidence spectroscopy. The fragmentation of the ions is dominated by loss of CO, C2H4, and C2H5, leading to daughter ions at m/z 56 and 55. Exploring the C5H8O. + potential energy surface reveals hydrogen tunneling to play an important role in low‐energy decarbonylation and probably also in the ethene‐loss processes, yielding 1‐butene and methylketene cations, respectively. At higher energies, pathways without a reverse barrier open up to oxopropenyl and cyclopropanone cations by ethyl‐radical loss and a second ethene‐loss channel, respectively. A statistical Rice–Ramsperger–Kassel–Marcus model is employed to test the viability of this mechanism. The pyrolysis of cyclopentanone is studied at temperatures ranging from about 800 to 1100 K. Closed‐shell pyrolysis products, namely 1,3‐butadiene, ketene, propyne, allene, and ethene, are identified based on their photoion mass‐selected threshold photoelectron spectrum. Furthermore, reactive radical species such as allyl, propargyl, and methyl are found. A reaction mechanism is derived incorporating both stable and reactive species, which were not predicted in prior computational studies.

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How to Compute Electron Ionization Mass Spectra from First Principles

Cited by 107 publications

References 127 publications

Spectroscopic Characterization of the Product Ions Formed by Electron Ionization of Adamantane

Spectroscopic Characterization of the Product Ions Formed by Electron Ionization of Adamantane

Identification of small molecules using accurate mass MS/MS search

Dissociative Ionization and Thermal Decomposition of Cyclopentanone

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