Collisionally activated dissociation: Effect of collision energy and collision cell pressure

1990 ◽  
Vol 19 (2) ◽  
pp. 94-96 ◽  
Author(s):  
Horst Schweer ◽  
Gerhard Mackert ◽  
Hannsjörg W. Seyberth
Keyword(s):  
Collision Energy ◽  
Collision Cell ◽  
Collisionally Activated Dissociation

Fragmentation of alkoxide ions following collisional activation. An energy-resolved study

1988 ◽  
Vol 66 (11) ◽  
pp. 2947-2953 ◽  
Author(s):  
Roger S. Mercer ◽  
Alex G. Harrison
Keyword(s):  
Kinetic Energy ◽  
Collisional Activation ◽  
Collision Energy ◽  
Relative Importance ◽  
Elimination Reaction ◽  
Proton Abstraction ◽  
Relative Stabilities ◽  
Collisionally Activated Dissociation ◽  
Reaction Channels ◽  
Alkane Elimination

The collisionally activated dissociation reactions of the C2 to C5 alkoxide ions have been studied for collisons occurring at 8 keV kinetic energy and also over the range 5 to 100 eV kinetic energy. The alkoxide ions fragment by 1,2-elimination of H2 and/or an alkane. Thus, primary alkoxide ions fragment by elimination of H2 only, secondary alkoxide ions show elimination of H2 and alkane molecules, while tertiary alkoxide ions show elimination of alkanes only. In alkane elimination, loss of CH4 is much more facilie than loss of larger alkanes. For secondary alkoxide ions, where more than one elimination reaction occurs, the energy dependence of fragmentation has been explored over the collision energy range 5 to 100 eV. The results are interpreted in terms of a step-wise mechanism involving formation of an anion-carbonyl compound ion-dipole complex, followed by proton abstraction by the H− or alkyl anion leading to the final products. The relative importance of the reaction channels is determined by the relative stabilities of these ion-dipole complexes.

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.

Collision-energy ramp. A modification to an RF-only quadrupole collision cell

1990 ◽  
Vol 4 (9) ◽  
pp. 341-344 ◽  
Author(s):  
Geoffrey Bott ◽  
Sherri Ogden ◽  
Julie A. Leary
Keyword(s):  
Collision Energy ◽  
Collision Cell ◽  
Quadrupole Collision Cell

scholarly journals In situ Rb-Sr dating by collision cell, multicollection inductively-coupled plasma mass-spectrometry with pre-cell mass-filter, (CC-MC-ICPMS/MS).

2021 ◽  
Author(s):  
Dan Bevan ◽  
Christopher David Coath ◽  
Jamie Lewis ◽  
Johannes B Schwieters ◽  
Nicholas Selwyn Lloyd ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Cell Mass ◽  
Quadrupole Mass Filter ◽  
Collision Cell ◽  
Uv Laser ◽  
Quadrupole Mass ◽  
Mass Filter ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

We document the utility for in situ Rb-Sr dating of a one-of-a-kind tribrid mass spectrometer, ‘Proteus’, coupled to a UV laser ablation system. Proteus combines a pre-cell quadrupole mass-filter,collision cell,...

scholarly journals On the scaling of fragmentation and energy dissipation in collisions of dust aggregates

2021 ◽  
Vol 23 (2) ◽  
Author(s):  
Philipp Umstätter ◽  
Herbert M. Urbassek
Keyword(s):  
Energy Dissipation ◽  
Collision Energy ◽  
Velocity Range ◽  
Collision Velocity ◽  
Granular Mechanics ◽  
Extra Factor ◽  
Cluster Fragmentation ◽  
Silica Clusters ◽  
Large Clusters ◽  
Small Clusters

Abstract Fragmentation of granular clusters may be studied by experiments and by granular mechanics simulation. When comparing results, it is often assumed that results can be compared when scaled to the same value of $$E/E_{\mathrm{sep}}$$ E / E sep , where E denotes the collision energy and $$E_{\mathrm{sep}}$$ E sep is the energy needed to break every contact in the granular clusters. The ratio $$E/E_{\mathrm{sep}}\propto v^2$$ E / E sep ∝ v 2 depends on the collision velocity v but not on the number of grains per cluster, N. We test this hypothesis using granular-mechanics simulations on silica clusters containing a few thousand grains in the velocity range where fragmentation starts. We find that a good parameter to compare different systems is given by $$E/(N^{\alpha }E_{\mathrm{sep}})$$ E / ( N α E sep ) , where $$\alpha \sim 2/3$$ α ∼ 2 / 3 . The occurrence of the extra factor $$N^{\alpha }$$ N α is caused by energy dissipation during the collision such that large clusters request a higher impact energy for reaching the same level of fragmentation than small clusters. Energy is dissipated during the collision mainly by normal and tangential (sliding) forces between grains. For large values of the viscoelastic friction parameter, we find smaller cluster fragmentation, since fragment velocities are smaller and allow for fragment recombination. Graphic abstract

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