ELECTRON TRANSFER TO MULTIPLY CHARGED IONS OF Ar, N2, N, AND O2

1967 ◽  
Vol 45 (4) ◽  
pp. 1451-1467 ◽  
Author(s):  
J. William McGowan ◽  
Larkin Kerwin
Keyword(s):  
Electron Transfer ◽  
Cross Sections ◽  
Large Scatter ◽  
Single Charge ◽  
Doubly Charged Ions ◽  
Multiply Charged ◽  
Double Electron ◽  
Doubly Charged ◽  
Charged Ions ◽  
Small Scatter

Cross sections for the transfer of one and of two electrons to fast doubly charged ions of Ar, O, N2, N, and to the triply charged ion of Ar are presented. The 20/02 reaction of Ar++ in Ar is resonant and smaller than that for Ar+ in Ar. The nonresonant, single-charge transfer process 20/11, even though it is exothermic, required that 12.5 ± 2.0 eV be transferred to the reaction from the kinetic energy of the projectile for the reaction to go. Consequently, the scatter of the fast Ar+ products is very large. Similarly, large scatter is observed for the double-electron transfer to Ar+++ as the ion traverses an argon target. Unlike the above, however, single- and double-electron transfer to O++ from O2 and to N2++ from N2, double transfer from Ar to Ar++, and single and triple transfer from Ar to Ar+++ show but small scatter.

scholarly journals Formation and fragmentation of doubly and triply charged ions in the negative ion spectra of neutral N-glycans from viral and other glycoproteins

2021 ◽  
Author(s):  
David J. Harvey ◽  
Weston B. Struwe ◽  
Anna-Janina Behrens ◽  
Snezana Vasiljevic ◽  
Max Crispin
Keyword(s):  
Detailed Comparison ◽  
Negative Ion ◽  
Doubly Charged Ions ◽  
Multiply Charged ◽  
Structural Details ◽  
Different Types ◽  
Doubly Charged ◽  
Ion Collision ◽  
Charged Ions

AbstractStructural determination of N-glycans by mass spectrometry is ideally performed by negative ion collision-induced dissociation because the spectra are dominated by cross-ring fragments leading to ions that reveal structural details not available by many other methods. Most glycans form [M – H]- or [M + adduct]- ions but larger ones (above approx. m/z 2000) typically form doubly charged ions. Differences have been reported between the fragmentation of singly and doubly charged ions but a detailed comparison does not appear to have been reported. In addition to [M + adduct]- ions (this paper uses phosphate as the adduct) other doubly, triply, and quadruply charged ions of composition [Mn + (H2PO4)n]n- have been observed in mixtures of N-glycans released from viral and other glycoproteins. This paper explores the formation and fragmentation of these different types of multiply charged ions with particular reference to the presence of diagnostic fragments in the CID spectra and comments on how these ions can be used to characterize these glycans. Graphical abstract

A collisionally activated dissociation (CAD) and computational investigation of doubly and singly charged DMSO complexes of Cu2+

2005 ◽  
Vol 83 (11) ◽  
pp. 1921-1935 ◽  
Author(s):  
John A Stone ◽  
Timothy Su ◽  
Dragic Vukomanovic
Keyword(s):  
Electron Transfer ◽  
Collision Energy ◽  
Nbo Analysis ◽  
Computational Investigation ◽  
Doubly Charged Ions ◽  
Collisionally Activated Dissociation ◽  
The Difference ◽  
Singly Charged ◽  
Doubly Charged ◽  
Charged Ions

The singly and doubly charged Cu(II)–DMSO complexes formed by electrospray have been examined by CAD and computation. The CAD spectra were obtained as a function of collision energy. The doubly charged ions, [Cu(DMSO)n]2+, were observed only for n ≥ 2. For n = 3, dissociation leads mainly to [Cu(DMSO)2]+ + DMSO+, with only a trace of [Cu(DMSO)2]2+. Although [Cu(DMSO)]2+ was never detected, computation shows that the n = 1 complex exists in a potential well. Loss of DMSO+ is computed to be exothermic for n = 1–3, the exothermicity decreasing as n increases. The singly charged complexes in the ESI spectra were [CuX(DMSO)n]+ (X = Cl, Br, NO3, HSO4, n = 1 or 2). The CAD spectra showed competition between electron transfer from anion to metal followed by loss of X and loss of DMSO+. Experiment and computation show that for [CuX(DMSO)]+, loss of X is the preferred decomposition at low collision energy. NBO analysis shows that electron transfer to Cu from DMSO decreases in [Cu(DMSO)n]2+ as n increases, the bonding becoming more electrostatic and less covalent. In [CuX(DMSO)n]+, the negative charge on X is much less than unity with most of the difference appearing on the DMSO ligand(s).Key words: copper–DMSO complexes, electrospray, CAD, structures.

Evidence from SIMS of Doubly-Charged Boron Contamination During Singly Charged-Ion Implantation

1990 ◽  
Vol 48 (2) ◽  
pp. 316-317
Author(s):  
D. S. Simons ◽  
P. H. Chi ◽  
D. B. Novotny
Keyword(s):  
Ion Implantation ◽  
Main Peak ◽  
Charged State ◽  
Exchange Reactions ◽  
Doubly Charged Ions ◽  
Multiply Charged ◽  
Residual Gas ◽  
Singly Charged ◽  
Doubly Charged ◽  
Charged Ions

When a dopant is introduced into a semiconductor material by ion implantation, it is sometimes desirable to accelerate and implant the ion in a multiply-charged state. This has the effect of increasing the energy and range of the ion without increasing the accelerating potential. Most modern ion implanters are of the pre-analysis type. In this design the ions are first accelerated through a modest extraction potential, e.g., 25 keV. This is followed by deflection for mass-to-charge selection in an analyzer magnet, after which the selected ions undergo final acceleration. Charge-exchange reactions between the doubly-charged ions and residual gas have been found to occur between the analyzing magnet and the final acceleration section. These reactions produce singly-charged ions that receive only half of the energy of the doubly-charged ions during final acceleration. For the case of B++ implantation the resulting implant profile shows a shallow-depth shoulder due to B+, the amplitude of which may be greater than 50% of the main peak.

Massenspektroskopische Festkörperuntersuchungen verbesserter Reproduzierbarkeit mit dem Gleichstrom-Abreißfunken im Vakuum zur lonenerzeugung

1963 ◽  
Vol 18 (8-9) ◽  
pp. 926-941 ◽  
Author(s):  
K. D. Schuy ◽  
H. Hintenberger
Keyword(s):  
Mass Spectra ◽  
Multiply Charged Ions ◽  
Doubly Charged Ions ◽  
Multiply Charged ◽  
Singly Charged ◽  
Main Component ◽  
Doubly Charged ◽  
Charged Ions ◽  
Spectrum Evaluation ◽  
Speed Of Analysis

Mass spectra obtained with the disjunctive d.c.-spark in vacuum show considerable improvement in accuracy and reproducibility over the conventional r.f.-spark of the DEMPSTER type. Higher ion currents increase the speed of analysis. A number of mass spectra were produced with a spectroscopic steel standard. The methods of visual and photometric spectrum evaluation are discussed in detail, using two quantities defined as “element sensitivity” and “normalized ionization sensitivity”. The former is a measure of how much more sensitive a given element can be photographically detected with the mass spectrograph than the main component of the sample (matrix element), while the latter indicates how much more sensitive multiply-charged ions of an element can be detected on the plate than singly-charged ions of the same element. Both element- and ionization sensitivities are reproducible to within approximately 20%. Furthermore, it is found, for most elements investigated, that the lines due to doubly-charged ions are more intense than those due to singly-charged ions and that the differences of element sensitivities of various elements decrease for ions of higher charge. The reproducibility of multiply-charged ions permits their use in the quantitative analysis of the sample.

Electron transfer dissociation of a melectin peptide: correlating the precursor ion structure with peptide backbone dissociations

2011 ◽  
Vol 76 (4) ◽  
pp. 295-309 ◽  
Author(s):  
Christopher L. Moss ◽  
Thomas W. Chung ◽  
Václav Čeřovský ◽  
František Tureček
Keyword(s):  
Electron Transfer ◽  
Density Functional ◽  
Electron Transfer Dissociation ◽  
Electron Attachment ◽  
Point Energy ◽  
Doubly Charged Ions ◽  
Fragment Ions ◽  
Gradient Optimization ◽  
Doubly Charged ◽  
Charged Ions

Electron transfer dissociation (ETD) of doubly and triply charged ions from the amphipathic N-terminal decapeptide GFLSILKKVL-NH2 segment of melectin gave different distributions of fragment ions. The triply charged ions generated extensive series of fragment ions of c and z type that covered the entire sequence from both the N and C termini. In contrast, electron transfer to the doubly charged ions caused backbone cleavages that occurred at residues close to the N and C termini. Attachment of a free low-energy electron to the doubly charged ions caused primary dissociations close to the N and C termini that were followed by consecutive dissociations of z ions. The structure of gaseous doubly charged ions from the melectin peptide was elucidated by a combination of exhaustive conformational search by force-field molecular dynamics, large-scale gradient optimization using the semiempirical PM6 method, and density functional theory single-point energy and gradient optimization calculations. The most stable doubly charged ions were found to be protonated at the lysine ε-amino groups and have globular conformations. The backbone cleavages in ETD correlated with the electronic structure of cation-radicals produced by electron attachment to the most stable conformers. The charged lysine ammonium groups direct the incoming electron to the π* orbitals at the proximate amide groups at Phe, Leu, Lys and Val residues that show the highest spin densities. Electron attachment at these amide groups weakens the N–Cα bonds between the Phe-Leu, Leu-Ser, Lys-Lys and Lys-Val residues and causes backbone dissociations.

Partial charge transfer of doubly charged ions

1956 ◽  
Vol 235 (1202) ◽  
pp. 354-358 ◽  
Keyword(s):  
Charge Transfer ◽  
Potential Energy ◽  
Cross Sections ◽  
Partial Charge ◽  
Partial Charge Transfer ◽  
Doubly Charged Ions ◽  
Low Energies ◽  
Double Charge ◽  
Doubly Charged ◽  
Charged Ions

Measurements of the partial charge transfer cross-sections for doubly charged ions X 2+ + Y → Y + + X + are described for C 2+ , N 2+ , A 2+ in He, Ne, A, and the results are discussed in terms of divergence from near-àdiabatic conditions caused by the crossing of potential energy curves. The single endothermic case C 2+ in He behaves adiabatically; all the others, which are exothermic, show large cross-sections at low energies. In the case A 2+ in A there is a contribution from double charge transfer, which cannot be distinguished experimentally from partial charge transfer.

A Discussion on photoelectron spectroscopy - Multiple photoelectron processes and their relationship to electron energy spectra

1970 ◽  
Vol 268 (1184) ◽  
pp. 163-167 ◽  
Keyword(s):  
Electron Energy ◽  
Cross Sections ◽  
Electron Emission ◽  
Photoelectron Spectroscopy ◽  
Vacuum Ultraviolet ◽  
Doubly Charged Ions ◽  
Direct Emission ◽  
Doubly Charged ◽  
The Relationship ◽  
Charged Ions

Some processes are discussed in which more than one electron is ejected by an atom which absorbs a photon. Illustrations are given from the measured photoionization cross-sections in the production of X e2+, X e3+, Cd2+, and Zn2+ by monochromatic vacuum ultraviolet radiation of energy less than 85 eV . Of photons absorbed at 63 eV, 30% produce doubly charged ions in Xe and Cd, and 20% do so in Zn, all by direct emission. The role which double electron emission and single and multiple Auger electron emission may play in electron energy measurements is brought out, and the relationship with atomic theory is briefly discussed.

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