@article {2175,
	title = {Gas-phase proton-transfer pathways in protonated histidylglycine},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {22},
	number = {18},
	year = {2008},
	note = {ISI Document Delivery No.: 355WATimes Cited: 2Cited Reference Count: 23MacDonald, Brandon I. Thachuk, Mark},
	month = {Sep},
	pages = {2946-2954},
	type = {Article},
	abstract = {Pathways for proton transfer in the histidylglycine cation are examined in the gas-phase environment with the goal of understanding the mechanism by which protons may become mobile in proteins with basic amino acid residues. An extensive search of the potential energy surface is performed using density functional theory (DFT) methods. After corrections for zero-point energy are included, it is found that all the lowest energy barriers for proton transfer between the N-terminus and the imidazole ring have heights of only a few kcal/mol, while those between the imidazole ring and the backbone amide oxygen have heights of approximately 15 kcal/mol when the proton is moving from the ring to the backbone and only a few kcal/mol when moving from the backbone to the imidazole ring. In mass spectrometric techniques employing collision-induced dissociation to dissociate protein complex ions or to fragment peptides, these barriers can be overcome, and the protons mobilized. Copyright (C) 2008 John Wiley \& Sons, Ltd.},
	keywords = {COLLISION-INDUCED DISSOCIATION, fragmentation, IONIZATION, MASS-SPECTROMETRY, mobility, MODEL, ORIGIN, PEPTIDE IONS},
	isbn = {0951-4198},
	url = {<Go to ISI>://000259738700023},
	author = {MacDonald, B. I. and Thachuk, M.}
}
@article {2334,
	title = {Quadrupole excitation of ions in linear quadrupole ion traps with added octopole fields},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {19},
	number = {4},
	year = {2008},
	note = {ISI Document Delivery No.: 289ZDTimes Cited: 2Cited Reference Count: 24Zhao, XianZhen Granot, Ori Douglas, D. J.},
	month = {Apr},
	pages = {510-519},
	type = {Article},
	abstract = {Modeling and experimental studies of quadrupole excitation of ions in linear quadrupole traps with added octopole fields are described. An approximate solution to the equations of motion of ions trapped in a quadrupole with added octopole and dodecapole fields, with quadrupole excitation and damping is given. The solutions give the steady-state or stationary amplitudes of oscillation with different excitation frequencies. Trajectory calculations of the oscillation amplitudes are also presented. The calculations show that there can be large changes in the amplitude of ion oscillation with small changes in excitation frequency, on both the low and high-frequency sides of a resonance. Results of experiments with quadrupole excitation of reserpine ions in linear quadrupole traps with 2.0\%, 2.6\%, and 4.0\% added octopole fields are given. It is found that as the excitation frequency is changed, two resonances are generally observed, which are attributed to the motion in the x and y directions. The two resonances can have quite different intensities. Sudden jumps or sharp sided resonances are not observed, although in some cases asymmetric resonances are seen. The calculated frequency differences between the two resonances are in approximate agreement with the experiments.},
	keywords = {CLOUD, fragmentation, FREQUENCIES, MASS-SPECTROMETRY, OF-FLIGHT SYSTEM, PAUL TRAP, PENNING TRAP, RESONANCES},
	isbn = {1044-0305},
	url = {<Go to ISI>://000255091500006},
	author = {Zhao, X. Z. and Granot, O. and Douglas, D. J.}
}
@article {723,
	title = {Resonance enhanced multiphoton dissociation of polycyclic aromatic hydrocarbons cations in an RF ion trap},
	journal = {Chemical Physics Letters},
	volume = {373},
	number = {3-4},
	year = {2003},
	note = {ISI Document Delivery No.: 681BGTimes Cited: 7Cited Reference Count: 35},
	month = {May},
	pages = {292-298},
	type = {Article},
	abstract = {We present a novel method for recording the absorption spectra of cations of non-volatile molecules using resonance enhanced multiphoton dissociation of trapped ions. Ions are produced through a 2-1aser desorption/ionization process in an RF ion trap mass-spectrometer. A third tunable visible laser induces fragmentation of the trapped ions with a yield dependent on the absorption cross-sections of the ions. Using this method we have recorded the visible absorption spectrum of two PAH isomers, phenanthrene and anthracene. (C) 2003 Elsevier Science B.V. All rights reserved.},
	keywords = {ENERGETICS, fragmentation, GAS-PHASE, IONIZATION, IR EMISSION, MASS-SPECTROMETRY, PAHs, PHOTODISSOCIATION, RADICAL CATIONS, SPECTROSCOPY},
	isbn = {0009-2614},
	url = {<Go to ISI>://000183016300010},
	author = {Rolland, D. and Specht, A. A. and Blades, M. W. and Hepburn, J. W.}
}
