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Article
Structural and Energetic Effects of O2′-Ribose Methylation of Protonated Pyrimidine Nucleosides
The 2′-substituents distinguish DNA from RNA nucleosides. 2′-O-methylation occurs naturally in RNA and plays important roles in biological processes. Such 2′-modifications may alter the hydrogen-bonding intera...
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Article
Activation of Water by Thorium Cation: A Guided Ion Beam and Quantum Chemical Study
The reaction of atomic thorium cations with deuterated water as a function of kinetic energy from thermal to 10 eV was studied using guided ion beam tandem mass spectrometry. At thermal energies, both ThO+ + D2 a...
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Article
Thermodynamics and Reaction Mechanisms for Decomposition of a Simple Protonated Tripeptide, H+GAG: a Guided Ion Beam and Computational Study
We present a thorough characterization of fragmentations observed in threshold collision-induced dissociation (TCID) experiments of protonated glycylalanylglycine (H+GAG) with Xe using a guided ion beam tandem ma...
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Article
Protonated Asparaginyl-Alanine Decomposition: a TCID, SORI-CID, and Computational Analysis
Deamidation of asparagine residues, one of the fastest known post-translational modifications in proteins, plays a significant role in various biological functions and degenerative, aging diseases. Here, we pr...
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Article
Spectroscopic Identification of the Carbyne Hydride Structure of the Dehydrogenation Product of Methane Activation by Osmium Cations
The present work explores the structures of species formed by dehydrogenation of methane (CH4) and perdeuterated methane (CD4) by the 5d transition metal cation osmium (Os+). Using infrared multiple photon dissoc...
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Article
Activation of CO2 by Gadolinium Cation (Gd+): Energetics and Mechanism from Experiment and Theory
The exothermic and barrierless activation of CO2 by the lanthanide gadolinium cation (Gd+) to form GdO+ and CO is investigated in detail using guided ion beam tandem mass spectrometry (GIBMS) and theory. Kinetic ...
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Article
How Hot are Your Ions Really? A Threshold Collision-Induced Dissociation Study of Substituted Benzylpyridinium “Thermometer” Ions
The first absolute experimental bond dissociation energies (BDEs) for the main heterolytic bond cleavages of four benzylpyridinium “thermometer” ions are measured using threshold collision-induced dissociation...
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Article
Thermodynamics and Reaction Mechanisms of Decomposition of the Simplest Protonated Tripeptide, Triglycine: A Guided Ion Beam and Computational Study
We present a thorough characterization of fragmentations observed in threshold collision-induced dissociation (TCID) experiments of protonated triglycine (H+GGG) with Xe using a guided ion beam tandem mass spectr...
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Article
Thermodynamics and Mechanism of Protonated Cysteine Decomposition: A Guided Ion Beam and Computational Study
A quantitative molecular description of the decomposition of protonated cysteine, H+Cys, is provided by studying the kinetic energy dependence of threshold collision-induced dissociation (CID) with Xe using a gui...
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Article
Critical Evaluation of Kinetic Method Measurements: Possible Origins of Nonlinear Effects
The kinetic method is a widely used approach for the determination of thermochemical data such as proton affinities (PA) and gas-phase acidities (ΔH° acid ). The...
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Article
The Power of Accurate Energetics (or Thermochemistry: What is it Good for?)
The utility of measuring the energetics of ion-molecule reactions is discussed. After distinguishing between the terms of thermodynamics (macroscopic, equilibrium quantities) and energetics (microscopic and ki...
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Article
Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Computational Study
We present a full computational description of the fragmentation reactions of protonated diglycine (H+GG). Relaxed potential energy surface scans performed at B3LYP/6-31 G(d) or B3LYP/6-311 + G(d,p) levels are us...
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Article
Thermodynamics and Mechanisms of Protonated Diglycine Decomposition: A Guided Ion Beam Study
We present a full molecular description of fragmentation reactions of protonated diglycine (H+GG) by studying their collision-induced dissociation (CID) with Xe using a guided ion beam tandem mass spectrometer (G...
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Article
In-source fragmentation technique for the production of thermalized ions
Our electrospray ionization-ion funnel-rf hexapole (ESI-IF-6P) source is designed to produce ions for threshold collision-induced dissociation (TCID) studies in a guided ion beam mass spectrometer. This ion so...
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Article
Ion mobility studies of electronically excited states of atomic transition metal cations: Development of an ion mobility source for guided ion beam experiments
The design of an ion mobility source developed to couple to a guided ion beam tandem mass spectrometer is presented. In these exploratory studies, metal ions are created continuously by electron ionization of ...
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Article
An electrospray ionization source for thermochemical investigation with the guided ion beam mass spectrometer
An electrospray ionization (ESI) source developed for use with the guided ion beam tandem mass spectrometer (GIBMS) is described. For accurate determination of thermochemistry using threshold collision-induced...
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Chapter
Threshold Collision-Induced Dissociations for the Determination of Accurate Gas-Phase Binding Energies and Reaction Barriers
Over the past two decades, an analysis of the kinetic energy dependence of ion molecule reactions has proven to yield accurate thermochemistry for a wide range of interesting chemical species. In this article,...
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Article
Mass spectrometry—Not just a structural tool: The use of guided ion beam tandem mass spectrometry to determine thermochemistry
Guided ion beam tandem mass spectrometry has proved to be a robust tool for the measurement of thermodynamic information. Over the past twenty years, we have elucidated a number of factors necessary to make su...
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Article
Collision-induced dissociation and theoretical studies of Cu+-dimethoxyethane complexes
Collision-induced dissociation of the dimethoxyethane (DXE) complexes with copper ions, Cu+(DXE)n, n = 1 and 2, is studied using kinetic energy dependent guided ion beam mass spectrometry. For Cu+(DXE)2, the only...
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Article
Entropy measurements and the kinetic method: A statistically meaningful approach
In the literature, data obtained using the kinetic method have been analyzed to provide both ion affinities and relative entropies for the competitive dissociations involved. In this work, the procedure used t...
