A mass spectrometer for studying chemical reactions

1963 ◽  
Vol 274 (1358) ◽  
pp. 285-292 ◽  
Keyword(s):  
Electron Beam ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Ion Source ◽  
Line Of Sight ◽  
Pyrolysis Products ◽  
Ionization Region ◽  
Differential Pumping ◽  
Hot Filament ◽  
Phase Chemical

This paper describes a mass spectrometer designed to study gas-phase chemical kinetics. An ion source has been constructed which incorporates a differentially pumped, electron beam filament chamber, and line-of-sight access from the sampling pinhole to the ionization region. Experiments are described which test the effectiveness of differential pumping in reducing contamination of the sample by pyrolysis products formed from the sample on the hot filament.

The gas phase reactivity of the dimethylchloronium ion with alkylbenzenes

1981 ◽  
Vol 59 (15) ◽  
pp. 2412-2416 ◽  
Author(s):  
John A. Stone ◽  
Margaret S. Lin ◽  
Jeffrey Varah
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Aromatic Hydrocarbons ◽  
Relative Rate ◽  
Ion Source ◽  
Nucleophilic Displacement ◽  
Rate Of Reaction ◽  
Displacement Reactions ◽  
Bonded Complexes

The reactivity of the dimethylchloronium ion with a series of aromatic hydrocarbons has been studied in a high pressure mass spectrometer ion source using the technique of reactant ion monitoring. Benzene is unreactive but all others, from toluene to mesitylene, react by CH3+ transfer to yield σ-bonded complexes. The relative rate of reaction increases with increasing exothermicity in line with current theories of nucleophilic displacement reactions.

Initial Calibration Results of the NIM Flight Spare Mass spectrometer for Exploration of Jupiter’s Icy Moons Exospheres

2021 ◽  
Author(s):  
Martina Föhn ◽  
Marek Tulej ◽  
André Galli ◽  
Audrey Helena Vorburger ◽  
Davide Lasi ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Surface Composition ◽  
European Space Agency ◽  
Ion Source ◽  
Icy Moons ◽  
Neutral Particles ◽  
Neutral Gas ◽  
High Speeds ◽  
Space Agency ◽  
Ionization Region

<p>The search for life is one of the key topics in modern space science. The JUICE mission of the European Space Agency ESA will investigate Jupiter and its icy moons Ganymede, Callisto and Europa, with Europa being an example of a potentially habitable world around a giant gas planet. The Particle and Environment Package, PEP, on board of the JUICE spacecraft will investigate Jupiter’s icy moons and their environment. The Neutral gas and Ion Mass spectrometer NIM will investigate the icy moon’s exospheres to investigate their formation and the interaction processes of the exospheres with the moons’ surface and Jupiter’s strong magnetic field. It will enhance our understanding of the processes involved in the interactions of ion bombardment on the icy moons' surfaces. From these measurements, we will derive the moons’ surface composition and their formation processes.</p><p>NIM is a time-of-flight mass spectrometer with two particle entrances: an open-source entrance to measure neutral particles and ions directly and a close source entrance where neutral particles get thermalized before entering the sensor’s ionization region. This allows detecting of particles with high speeds. NIM has a specially designed ion storage source and an ion-mirror to double the flight distance of the produced ions by keeping the sensor at a minimal size.</p><p>In this contribution, we show calibration results of the NIM flight spare instrument on one hand operated with laboratory and on the other operated with flight electronics. We demonstrate the performance of NIMs ion-source, verify the performance of the closed-source antechamber. NIM has a demonstrated mass resolution of m/Δm 800.</p>

Kinetics and Rate Constants of Reactions Leading to Hydration of and in Gaseous Oxygen, Argon, and Helium Containing Traces of Water

1972 ◽  
Vol 50 (14) ◽  
pp. 2230-2235 ◽  
Author(s):  
J. D. Payzant ◽  
A. J. Cunningham ◽  
P. Kebarle
Keyword(s):  
High Pressure ◽  
Electron Beam ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Rate Constants ◽  
Gas Phase Reactions ◽  
Third Order ◽  
Gaseous Oxygen ◽  
Time Resolved ◽  
Pulsed Electron Beam

The rate constants for the forward and reverse components of gas phase reactions:[Formula: see text]were measured with a pulsed electron beam, time resolved detection high pressure mass spectrometer at 300 °K. O2, Ar, and He at pressures from 1–7 Torr were used as third gas M. The forward reactions were found to be third order and the reverse reactions second order. Establishment of the equilibria could also be observed.

Stabilities of complexes (N2)nH+, and (O2)nH+ for n = 1 to 7 based on gas phase ion-equilibria measurements

1979 ◽  
Vol 57 (16) ◽  
pp. 2159-2166 ◽  
Author(s):  
K. Hiraoka ◽  
P. P. S. Saluja ◽  
P. Kebarle
Keyword(s):  
Electron Beam ◽  
Gas Phase ◽  
Equilibrium Constants ◽  
Ion Source ◽  
Large Decrease ◽  
Proton Affinities ◽  
Source Pressure ◽  
Pulsed Electron Beam ◽  
The Stability ◽  
Gas Phase Ion

The equilibria Bn−1H+ + B = BnH+ for B = N2, CO, and O2 were measured with a pulsed electron beam high ion source pressure mass spectrometer. Equilibria up to n = 7 could be observed. van't Hoff plots of the equilibrium constants lead to ΔGn−1,n0, ΔHn−1,n0, and ΔSn−1,n0. While the proton affinities increase in the order O2 < N2 < CO, the stabilities of the B2H+ towards dissociation to BH+ + B increase in the reverse order, i.e. CO < N2 < O2. The stabilities towards dissociation of B for BnH+ where n > 2 are much lower for all three compounds; however for N2 and CO the stability decreases only very slowly from n = 3 to n = 6, then there is a large fall off for n = 7. The (O2)nH+ clusters show large decrease of stabilities as n increases. The BnH+ (for n > 3) of CO are more stable than those of N2 or O2. The above experimental results can be partially explained with the help of results from molecular orbital STO-3G calculations for B, BH+, and B2H+ and general considerations. BH+ and B2H+ for CO and N2 are found to be linear while those for O2 are bent. The most stable O2H+ is a triplet, while (O2)2H+ is a quintuplet.

Ion-molecule reactions in uranium hexafluoride

1975 ◽  
Vol 28 (9) ◽  
pp. 1879 ◽  
Author(s):  
NA McAskill
Keyword(s):  
Kinetic Energy ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Uranium Hexafluoride ◽  
Ion Source ◽  
Rate Coefficients ◽  
Medium Pressure ◽  
Ion Molecule Reactions ◽  
Ion Kinetic Energy

The ion-molecule reactions of UF6 in the gas phase were studied in a mass spectrometer fitted with a medium-pressure ion source. The main reactions were the collision-stabilized formation of U2F11+ from UF5+, U2F10+ from UF4+ and U3F16+ from U2F10+. Rate coefficients for the reactions of UF5+ and UF4+ with UF6 and the distribution of their products were found to depend upon the ion kinetic energy.

Selective chemical etching of hexagonal boron nitride compared to cubic boron nitride

1997 ◽  
Vol 12 (2) ◽  
pp. 412-415 ◽  
Author(s):  
Stephen J. Harris ◽  
Anita M. Weiner ◽  
Gary L. Doll ◽  
Wen-Jin Meng
Keyword(s):  
Boron Nitride ◽  
Gas Phase ◽  
Chemical Etching ◽  
Hexagonal Boron Nitride ◽  
Cubic Boron Nitride ◽  
Chemical Etch ◽  
Selective Chemical ◽  
Hot Filament ◽  
Selective Chemical Etching ◽  
Phase Chemical

A BN film containing comparable amounts of sp2 and sp3 phases was subjected to a gas-phase chemical etch in a hot-filament environment containing 1% CH4 in H2. After a partial etch, examination by FTIR shows that the sp2 was preferentially etched, leaving a larger sp3 fraction than in the unetched film. The possibility that preferential etching could be used to increase the purity of cBN films is discussed.

A PULSED ION SOURCE FOR THE STUDY OF UNIMOLECULAR AND BIMOLECULAR REACTIONS OF GAS-PHASE IONS

1965 ◽  
Vol 43 (1) ◽  
pp. 159-174 ◽  
Author(s):  
T. W. Shannon ◽  
F. Meyer ◽  
A. G. Harrison
Keyword(s):  
Reaction Time ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Rate Constant ◽  
Thermal Energy ◽  
Ion Source ◽  
Operating Characteristics ◽  
Bimolecular Reactions ◽  
Molecule Reaction ◽  
Gas Phase Ions

A pulsed ion source has been constructed for use with a magnetic-deflection mass spectrometer. With this source the time between ion formation and withdrawal for analysis can be controlled and varied in a known manner. The design and operating characteristics of the source are discussed and a technique is described for the measurement of ion withdrawal times using the pulsing technique. The rate constant for the ion molecule reaction[Formula: see text]has been determined for the reaction of thermal energy ions using reaction time as the experimental variable. The equivalent reactions in the deuteriomethanes have also been studied. Preliminary results obtained in the study of the unimolecular fragmentation of the cyclohexadiene, toluene, and spiroheptadiene parent ions are presented.

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