Measurement of Ion–Molecule Reaction Rate Constants Using Ion Cyclotron Resonance

1969 ◽  
Vol 50 (10) ◽  
pp. 4125-4132 ◽  
Author(s):  
S. E. Buttrill
Keyword(s):  
Rate Constants ◽  
Cyclotron Resonance ◽  
Reaction Rate ◽  
Ion Cyclotron Resonance ◽  
Reaction Rate Constants ◽  
Molecule Reaction ◽  
Ion Cyclotron

Chemistry of (and on) Transition Metal Clusters: A Fourier Transform Ion Cyclotron Resonance Study of the Reaction of Niobium Cluster Cations with Nitric Oxide

2009 ◽  
Vol 15 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Daniel J. Harding ◽  
Thomas A.A. Oliver ◽  
Tiffany R. Walsh ◽  
Thomas Drewello ◽  
D. Phil Woodruff ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Fourier Transform ◽  
Rate Constants ◽  
Cyclotron Resonance ◽  
Main Reaction ◽  
Ion Cyclotron Resonance ◽  
Transition Metal Clusters ◽  
Reaction Rate Constants ◽  
Ion Cyclotron ◽  
Small Clusters

The reactions of niobium cluster cations, Nb+ n ( n = 2–19), with nitric oxide have been investigated using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR). The overall reaction rate constants are found to be in reasonable agreement with collision rates calculated using the surface charge capture model. The dominant reaction for small clusters ( n < 9) involves reaction-induced fragmentation resulting in the loss of either NbO or NbN. By contrast, the main reaction observed for the larger clusters ( n > 11) is sequential NO chemisorption. Clusters n = 9, 10 exhibit both extremes of behaviour and are the only clusters upon which there is evidence of NO decomposition with N2 loss observed whenever multiple NO molecules are co-adsorbed. The rate constants for each process have been determined as a function of cluster size.

Mechanism and Structure in the Ion Chemistry of Tetramethyldiphosphine: An Ion Cyclotron Resonance Spectrometric Study

1976 ◽  
Vol 31 (5) ◽  
pp. 414-421 ◽  
Author(s):  
Karl-Peter Wanczek
Keyword(s):  
Mass Spectrum ◽  
Rate Constants ◽  
Cyclotron Resonance ◽  
Double Resonance ◽  
Ion Cyclotron Resonance ◽  
Spectrometric Study ◽  
Ion Chemistry ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Ion Cyclotron Resonance Spectrometry

Abstract The mass spectrum of tetramethyldiphosphine and the ion chemistries of this compound and of its mixtures with phosphine and dimethylphosphine have been investigated by ion cyclotron resonance spectrometry. Numerous ion molecule reactions have been observed. The rate constants of the two most abundant ions formed by the molecular ion, the tetramethyldiphosphonium ion, H(CH3)2P-P(CH3)2+ and the hexamethyltriphosphonium ion, P3(CH3)6+ , are k2.35≦0.1X10-10 cm3 molecule-1 s-1 and k2.40 = 1.5 X10-10 cm3 molecule -1 s -1 respectively. The structures of several ions have been determined with the aid of their ion-molecule reactions. The ions m/e = 79 and 93 are thought to have the structures HP - P(CH3)H+ and HP-P(CH3)2+ . The most probable structures of the ions m/e = 169 and 183 are HP(CH3)2-P(CH3)-P(CH3)2+ and (CH3)2P-P(CH3) - P(CH3)3+ . The protonated molecule undergoes several ion-molecule reactions, which proceed via an intermediate, m/e = 183, [(CH3)6P3+]* which is detected by double resonance experiments.

Mass Spectra and Ion Chemistry of Methylphosphine, Dimethylphosphine and Dimethyldeuterophosphine, Investigated by Ion Cyclotron Resonance Spectrometry

1975 ◽  
Vol 30 (3) ◽  
pp. 329-339 ◽  
Author(s):  
Karl-Peter Wanczek
Keyword(s):  
Rate Constants ◽  
Cyclotron Resonance ◽  
Mass Spectra ◽  
Ion Cyclotron Resonance ◽  
Exchange Reactions ◽  
Ion Chemistry ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Product Ions ◽  
Ion Cyclotron Resonance Spectrometry

The mass spectra and the ion molecule reactions of methylphosphine, dimethylphosphine and dimethyldeuterophosphine have been studied by ion cyclotron resonance spectrometry. About 50 ion molecule reaction are observed for each compound. The product ions can be classified as ions with two phosphorus atoms: P2R5+, P2R3+, P2R2+ and P2R+ (R = CH3 or H), as phosphonium and phosphinium ions and ions resulting from collision dissociations and charge exchange reactions. Tertiary ions with three phosphorus atoms like CH3P3H2+ (from CH3PH2) and (CH3)4P3H2 (from (CH3)2PH) have also been detected. The mechanisms of the ion molecule reactions, rearrangements, P -H- and C-H-reactivities and product ion structures are discussed, using in the case of dimethylphosphine the results obtained with the deuterated compound. Rate constants of formation of the more abundant product ions from the molecular ion and the CH3P+ ion, both odd electron particles, have been determined. The reactions with dimethylphosphine have much smaller rate constants than the reactions with methylphosphine.

An abinitio and ion cyclotron resonance study of the protonation of borazine

1979 ◽  
Vol 57 (14) ◽  
pp. 1751-1757 ◽  
Author(s):  
C. E. Doiron ◽  
F. Grein ◽  
T. B. McMahon ◽  
K. Vasudevan
Keyword(s):  
Ab Initio ◽  
Proton Affinity ◽  
Cyclotron Resonance ◽  
Molecular Ions ◽  
Ion Cyclotron Resonance ◽  
Molecule Reaction ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Gas Phase Ion ◽  
Protonated Nitrogen Atom

The gas phase ion–molecule reactions and proton affinity of borazine have been investigated by both theoretical ab initio and ion cyclotron resonance techniques. The experimental proton affinity has been determined from competitive proton transfer equilibria with standard reference bases and found to be 196.4 ± 0.2 kcal/mol. Ion–molecule reaction schemes for reaction of borazine molecular ions have been proposed. Ab initio calculations find the proton affinity of borazine to be 203.4 kcal/mol and the most energetically favorable structure of the borazinium ion is one in which very little structural change occurs relative to neutral borazine with the exception of the geometry about the protonated nitrogen atom. Charge distributions and bond lengths are used to explain bonding changes upon protonation.

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