Spelling suggestions: "subject:"spectrometry."" "subject:"pectrometry.""
71 |
Application of coincidence ion mass spectrometry for chemical and structural analysis at the sub-micron scaleBalderas, Sara 01 November 2005 (has links)
Surfaces can be probed with a variant of secondary ion mass spectrometry
(SIMS) where the bombardment is with a sequence of single keV projectiles, each
resolved in time and space, coupled with the separate record of the secondary ions (SIs)
ejected from each projectile impact. The goal of this study was to demonstrate an
efficient mode of SIMS where one obtains valid analytical information with a minimum
of projectiles and hence a minimum of sample consumption. An inspection of the
ejected SIs from individual bombardment events will reveal ??super efficient?? collision
cascades i.e., events, where two or more secondary ions were emitted simultaneously. It
has been shown that these coincidental emissions can provide information about the
chemical composition of nano-domains.
Previous studies using coincidence counting mass spectrometry (CCMS)
indicated an enhancement of identifying correlations between SIs which share a common
origin. This variant of SIMS requires an individual projectile impact thus causing SI
emission from a surface area of ~5 nm in radius. Thus, in an event where two or moreSIs are ejected from a single projectile impact, they must originate from atoms and
molecules co-located within the same nano-domain.
Au nanorods covered by a 16-mercaptohexadecanoic acid (MHDA) monolayer
were analyzed using this methodology. A coincidence ion mass spectrum was obtained
for the MHDA monolayer covered Au nanorods which yielded a peak for a Au adduct.
Similar results were obtained for a sample with a MHDA monolayer on a Au coated Si
wafer.
A series of samples consisting of Cu aggregates and AuCu alloys were
investigated by SIMS to demonstrate that this technique is appropriate for characterizing
nanoparticles. The mass spectra of these samples indicated that Au200
4+ is an effective
projectile to investigate the surface of the target because it was able to penetrate through
the poly(vinylpyrrolidone) (PVP) stabilizer that coated the surface of these
nanoparticles. Coincidence mass spectra of the Cu aggregates yielded molecules colocated
within the same nano-domain.
Finally, this methodology was used to investigate surface structural effects on the
occurrence of ??super-efficient?? events. The results indicated that it is possible to
distinguish between two phases of ??-ZrP compounds although the stoichiometry remains
the same.
|
72 |
Intense-field ionization of atoms and molecules spatially resolved ion detection and ultrashort optical vortices /Strohaber, James. January 1900 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Sept. 16, 2008). PDF text: xvi, 196 p. : ill. (some col.) ; 9 Mb. UMI publication number: AAT 3297758. Includes bibliographical references. Also available in microfilm and microfiche formats.
|
73 |
A new technique for high performance tandem time-of-flight mass spectrometry /Katz, Daniel Louis. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 56-58). Also available online.
|
74 |
Ion cyclotron resonance studies of vibrationally excited ions I. Low intensity multiphoton dissociation of gas phase ions using CW CO2 laser radiation. II. Infrared radiative stabilization of energized species in the gas phase /Woodin, Richard Lawrence. Goddard, William A., Beauchamp, Jesse L. January 1979 (has links)
Thesis (Ph. D.)--California Institute of Technology, 1979. UM #79-11,639. / Advisor names found in the Acknowledgments pages of the thesis. Title from home page. Viewed 01/19/2010. Includes bibliographical references.
|
75 |
Studies of acid-base ion-molecule chemistry using ion cyclotron resonance techniques and photoelectron spectroscopyStaley, Ralph Horton. Beauchamp, Jesse L. January 1976 (has links)
Thesis (Ph. D.). UM #76-06,542. Thesis (Ph. D.)--California Institute of Technology, 1976. UM #76-06,542. / Advisor names found in the Acknowledgments pages of the thesis. Title from home page. Viewed 01/19/2010. Includes bibliographical references.
|
76 |
The investigation of gas-phase ion-molecule reactions with fourier transform ion cyclotron resonance mass spectrometryCrellin, Kevin Christopher. Goddard, William A., Beauchamp, Jesse L. January 1900 (has links)
Thesis (Ph. D.)--California Institute of Technology, 1997. UM #9800349. / Advisor names found in the Acknowledgments pages of the thesis. Title from home page. Viewed 01/21/2010. Includes bibliographical references.
|
77 |
Evaluation of metal binding interactions in host-guest chemistry using quadrupole ion trap mass spectrometry /Reyzer, Michelle Lee, January 2000 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references. Available also in a digital version from Dissertation Abstracts.
|
78 |
Investigation of tertiary structure of electrosprayed ribosomal protein L9 by Fourier transform ion cyclotron resonance mass spectrometry using low energy dissociation techniquesArmorgan, Carla Allison Patrice, Laude, David A., January 2003 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: Laude, David A. Vita. Includes bibliographical references. Available also from UMI Company.
|
79 |
Bioinformatics of proteomic tandem mass spectra : selection, characterization, and identification /Tabb, David L. January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p.113-118).
|
80 |
Mass spectrometry-based biomolecular recognition and response factor investigations using electrospray ionizationRaji, Misjudeen. January 2008 (has links)
Thesis ( Ph.D.) -- University of Texas at Arlington, 2008.
|
Page generated in 0.2267 seconds