Applications

Lindinger, W.; Howorka, F.; Shull, J. M.; Phelps, A. V.; Zipf, E. C.; Kim, Y.-K.; Futrell, J. H.

doi:10.1007/978-3-7091-4028-4_9

Cited by 3 publications

(3 citation statements)

References 146 publications

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“…Molecular ionization cross sections due to electron impact are required in many fields like mass spectrometry, modelling of planetary and cometary atmospheres, astrophysics, fusion physics, plasma diagnostics etc (Lindinger and Howorka 1985). However, due to the multi-centred nature of the target a quantum mechanical evaluation of these cross sections is a difficult task.…”

Section: Introductionmentioning

confidence: 99%

Electron impact ionization of methane

Khare

Sharma

Tomar

1999

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

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A simple model to calculate the total ionization cross sections of a molecule due to electron impact has been obtained by combining the useful features of the two previous models given by Kim and Rudd (1994 Phys. Rev. A 50 3954) and Saksena et al (1997 Physica B 233 201, 1997 Int. J. Mass Spectrom. Ion Process. 171 L1). It is shown that the Bethe and Mott cross section terms obtained by Kim and Rudd are the approximate forms of the present expressions. The calculated cross sections for the CH4 molecule are in satisfactory agreement with a number of experimental data over a wide energy range varying from 15 eV to 2.7 MeV. Although the present Bethe and Mott cross sections in the binary-encounter-Bethe model are different from the corresponding cross sections of Kim et al (1997 J. Chem. Phys. 106 1026), the total ionization cross sections obtained in these two investigations are very close to each other. For impact energies greater than about 40 eV the present cross sections are in good accord with those given by the Saksena model. However, at lower energies the present cross sections are greater than those given by the above model and are in better agreement with the experimental data. The present value of the collisional parameter is about 10% lower than the experimental value of Reike and Prepejchal (1972 Phys. Rev. A 6 1507).

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Section: Introductionmentioning

confidence: 99%

Electron impact ionization of methane

Khare

Sharma

Tomar

1999

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

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“…Characteristic fragment ions (product ions) generated in the ionization process are remarkable, as they normally provide important structural information relating to the precursor ions. More specifically, “hard” ionization techniques, such as electron (impact) ionization (EI), usually generates extensive fragment ions upon ionization, and sometimes the precursor ions (e.g., radical cations, M +● , in positive ion mode) are not even visible in the mass spectrum [ 19 , 20 ]. Moreover, because of its extremely high reproducibility, EI mass spectra have been used to establish libraries so that the identities of analyte ions can be, in many cases, confirmed by matching their measured EI spectra with the library data (false hits are still possible) [ 21 ].…”

Section: Technical Advances In Ms-based Structural Elucidation Techni...mentioning

confidence: 99%

Recent Advances in Mass Spectrometry-Based Structural Elucidation Techniques

2022

Molecules

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Mass spectrometry (MS) has become the central technique that is extensively used for the analysis of molecular structures of unknown compounds in the gas phase. It manipulates the molecules by converting them into ions using various ionization sources. With high-resolution MS, accurate molecular weights (MW) of the intact molecular ions can be measured so that they can be assigned a molecular formula with high confidence. Furthermore, the application of tandem MS has enabled detailed structural characterization by breaking the intact molecular ions and protonated or deprotonated molecules into key fragment ions. This approach is not only used for the structural elucidation of small molecules (MW < 2000 Da), but also crucial biopolymers such as proteins and polypeptides; therefore, MS has been extensively used in multiomics studies for revealing the structures and functions of important biomolecules and their interactions with each other. The high sensitivity of MS has enabled the analysis of low-level analytes in complex matrices. It is also a versatile technique that can be coupled with separation techniques, including chromatography and ion mobility, and many other analytical instruments such as NMR. In this review, we aim to focus on the technical advances of MS-based structural elucidation methods over the past five years, and provide an overview of their applications in complex mixture analysis. We hope this review can be of interest for a wide range of audiences who may not have extensive experience in MS-based techniques.

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“…Cross sections due to ionization are needed for modeling of radiation effects in materials and in biomedical research and modeling of fusion plasmas in tokomaks. The computed data on cross sections are necessary in studying the problems of radiative association [1,2]. Allene (C 3 H 4 ) and propane (C 3 H 8 ) are hydrocarbon molecules.…”

Section: Introductionmentioning

confidence: 99%

Electron impact ionization cross sections of allene and propane molecules at low and high energy range

Tiwari¹,

Kumar²,

Jain³

et al. 2012

JAMS

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We have made a study of the total ionization cross sections of hydrocarbon molecules (allene, propane) due to electron impact for single ionization. Electron impact ionization cross sections (EIICS) have been calculated from threshold ionization energy to high energy (10 MeV). Along with EIICS calculation the values of collisional parameters are also calculated. The theoretical model, developed by Khare, has been modified to calculate the electron impact ionization cross section for molecules and atoms. The predicted EIICS of allene and propane molecules are compared with other theoretical and experimental data. Present model prevail a high degree of goodness of cross sections to the experimental data. Adequate comparisons of collisional parameter have been made with other available experimental values.

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Applications

Cited by 3 publications

References 146 publications

Electron impact ionization of methane

Electron impact ionization of methane

Recent Advances in Mass Spectrometry-Based Structural Elucidation Techniques

Electron impact ionization cross sections of allene and propane molecules at low and high energy range

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