A method for calculating the shapes of peaks resulting from fragmentations of metastable ions in a mass spectrometer. II. Peak shapes arising from a distribution of kinetic energy releases: determination of distribution function

1980 ◽  
Vol 373 (1752) ◽  
pp. 13-25 ◽  
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Preceding Paper ◽  
Kinetic Energy Release ◽  
Peak Shape ◽  
Doubly Charged Ions ◽  
Metastable Ions ◽  
Product Ions ◽  
Doubly Charged

Following the calculations described in the preceding paper (part I), which determine the MIKE peak shape arising from a discrete kinetic energy release, a method is presented for extending the calculations for the determination of the kinetic energy release distribution, n (T), from any experimental peak shape. This new approach has the advantage, compared to previous work, that the distribution can be obtained directly and does not involve any trial and error methods. It applies equally well where discrimination occurs against some of the product ions having components of velocity parallel to the length of the instrument slits. A variety of peak shapes have been investigated and several examples are given of the energy release distribution for various ionic reactions. Charge separation reactions of doubly-charged ions have been examined and in one case, the reaction 91 2+ -> 52 + in toluene, the energy release function exhibits fine structure, which has not previously been observed.

Kinetic Energy Release and Metastable Transitions II. The Decomposition of Doubly-Charged Ions of Aliphatic and Alicyclic Hydrocarbons

1969 ◽  
Vol 24 (1) ◽  
pp. 134-138
Author(s):  
M. Barber ◽  
K. R . Jennings
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Kinetic Energy Release ◽  
Doubly Charged Ions ◽  
Fragment Ions ◽  
Degree Of Unsaturation ◽  
High Kinetic Energy ◽  
Double Focusing ◽  
Doubly Charged ◽  
Charged Ions

AbstractThe decompositions of doubly-charged ions given by a number of C3 -C8 aliphatic and alicyclic hydrocarbons have been investigated in a double-focusing mass spectrometer. Many processes were found in which high kinetic energy CH3+ and C2H3+ ions are formed. Doubly-charged ions fragment by more than one route and in many cases, high kinetic energy fragment ions are formed in at least two different ways. Metastable transitions common to several compounds were observed, the intensities rising as the degree of unsaturation increased.

scholarly journals Kinetic Energy Release in Metastable Transitions. I

1967 ◽  
Vol 22 (1) ◽  
pp. 15-19 ◽  
Author(s):  
M. Barber ◽  
K. R. Jennings ◽  
R. Rhodes
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Mass Spectrometer ◽  
Kinetic Energy Release ◽  
Peak Shape ◽  
Free Region ◽  
Field Free Region ◽  
Product Ions ◽  
Electrostatic Analyser

A method is described for detecting metastable transitions which take place with the release of kinetic energy in the field-free region between the source and electrostatic analyser of a doublefocusing mass spectrometer, and a procedure is given for evaluating the kinetic energy release. Values are given for a number of transitions and are in agreement with those obtained by other methods where comparison is possible. The variation of peak shape with accelerating voltage is ascribed to the varying efficiency with which product ions are collected.

Kinetic energy release and mean life time of metastable ions produced from C3H3N

Vacuum ◽  
2009 ◽  
Vol 83 ◽  
pp. S20-S23 ◽  
Author(s):  
K. Głuch ◽  
E. Szot ◽  
A. Gruszecka ◽  
M. Szymańska-Chargot ◽  
J. Cytawa ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Life Time ◽  
Kinetic Energy Release ◽  
Metastable Ions

The Role of Long-Range Forces in the Determination of Translational Kinetic Energy Release. Loss of C4H4+from the Benzene and Pyridine Cations

2008 ◽  
Vol 112 (41) ◽  
pp. 10086-10095 ◽  
Author(s):  
E. Gridelet ◽  
R. Locht ◽  
A. J. Lorquet ◽  
J. C. Lorquet ◽  
B. Leyh
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Long Range ◽  
Kinetic Energy Release

scholarly journals Ringöffnung CO+- und COOCH3+·-substituierter Cyclopropane und CO-Eliminierung aus isomeren C3H5CO+-Ionen / Ring Opening of CO+ and COOCH3+· Substituted Cyclopropanes and CO Loss from Isomeric C3H5CO+ Ions

1979 ◽  
Vol 34 (3) ◽  
pp. 488-494 ◽  
Author(s):  
Helmut Schwarz ◽  
Chrysostomos Wesdemiotis
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Ring Opening ◽  
Collisional Activation ◽  
Kinetic Energy Release ◽  
Ester Group ◽  
Molecular Ions ◽  
Peak Shape ◽  
Metastable Peak ◽  
Substituted Cyclopropanes

Abstract The non-decomposing molecular ions of methyl cyclopropanecarboxylate (14) are found to rearrange to ionised methyl but-3-enoate (15). For ions with sufficient internal energy to decompose, this isomerization is in competition with · OCH3 loss, via direct cleavage of the ester group. Collisional activation spectroscopy may be used to distinguish between the C3H5CO+ ions formed by · OCH3 loss from the molecular ions of 14, 15 and other isomeric precursors. Four distinct C3H5CO+ species (18-21) can be identified in this way; these C3H5CO+ ions may themselves decompose, via CO elimination. Consideration of the metastable peak shape for CO loss, in conjunction with collisional activation spectroscopy on the resulting C3H5+ -ions, leads to two main conclusions, (i) Two C3H5+ ions (22 and 27) exist in potential energy wells. The very narrow metastable peaks for CO loss from 19 and 21 (leading to 22 and 27, respectively) show that these processes are continuously endothermic. In contrast, CO loss from either 18 or 20 gives rise to much broader metastable peaks. This suggests that rate-determining rearrangement of the incipient C3H5+ cations, to a more stable isomer, occurs prior to decomposition, (ii) Elimination of CO from the [M- · OCH3]+ fragment of 14 gives rise to a composite metastable peak, thus indicating the occurrence of two competing channels for dissociation. These channels are assigned to CO loss from 18 (larger kinetic energy release) and CO loss from 19 (smaller kinetic energy release).

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