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in subjects: "Photoemission"  
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TOF Electron Energy Analyzer for Spin and Angular Resolved Photoemission Spectroscopy

Description: Current pulsed laser and synchrotron x-ray sources provide new opportunities for Time-Of- Flight (TOF) based photoemission spectroscopy to increase photoelectron energy resolution and efficiency compared to current standard techniques. The principals of photoelectron timing front formation, temporal aberration minimization, and optimization of electron beam transmission are presented. We have developed these concepts into a high resolution Electron Optical Scheme (EOS) of a TOF Electron Energy … more
Date: July 9, 2008
Creator: Lebedev, Gennadi; Jozwiak, Chris; Andresen, Nord; Lanzara, Alessandra & Hussain, Zahid
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Phase Segregation in Polystyrene?Polylactide Blends

Description: Spun-cast films of polystyrene (PS) blended with polylactide (PLA) were visualized and characterized using atomic force microscopy (AFM) and synchrotron-based X-ray photoemission electron microscopy (X-PEEM). The composition of the two polymers in these systems was determined by quantitative chemical analysis of near-edge X-ray absorption signals recorded with X-PEEM. The surface morphology depends on the ratio of the two components, the total polymer concentration, and the temperature of vacuu… more
Date: June 9, 2010
Creator: Leung, Bonnie; Hitchcock, Adam; Brash, John; Scholl, Andreas & Doran, Andrew
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

X-ray Spectromicroscopy Study of Protein Adsorption to a Polystyrene-Polylactide Blend

Description: Synchrotron-based X-ray photoemission electron microscopy (X-PEEM) was used to study the adsorption of human serum albumin (HSA) to polystyrene-polylactide (40:60 PS-PLA, 0.7 wt percent) thin films, annealed under various conditions. The rugosity of the substrate varied from 35 to 90 nm, depending on the annealing conditions. However, the characteristics of the protein adsorption (amounts and phase preference) were not affected by the changes in topography. The adsorption was also not changed b… more
Date: June 9, 2010
Creator: Leung, Bonnie; Hitchcock, Adam; Cornelius, Rena; Brash, John; Scholl, Andreas & Doran, Andrew
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ultrafast dynamics in helium nanodroplets probed by femtosecond time-resolved EUV photoelectron imaging

Description: The dynamics of electronically excited helium nanodroplets are studied by femtosecond time-resolved photoelectron imaging. EUV excitation into a broad absorption band centered around 23.8 eV leads to an indirect photoemission process that generates ultraslow photoelectrons. A 1.58 eV probe pulse transiently depletes the indirect photoemission signal for pump-probe time delays <200 fs and enhances the signal beyond this delay. The depletion is due to suppression of the indirect ionization pro… more
Date: July 9, 2010
Creator: Kornilov, Oleg; Wang, Chia C.; Buenermann, Oliver; Healy, Andrew T.; Leonard, Mathew; Peng, Chunte et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Stripe-to-bubble transition of magnetic domains at the spin reorientation of (Fe/Ni)/Cu/Ni/Cu(001)

Description: Magnetic domain evolution at the spin reorientation transition (SRT) of (Fe/Ni)/Cu/Ni/Cu(001) is investigated using photoemission electron microscopy. While the (Fe/Ni) layer exhibits the SRT, the interlayer coupling of the perpendicularly magnetized Ni layer to the (Fe/Ni) layer serves as a virtual perpendicular magnetic field exerted on the (Fe/Ni) layer. We find that the perpendicular virtual magnetic field breaks the up-down symmetry of the (Fe/Ni) stripe domains to induce a net magnetizati… more
Date: June 9, 2010
Creator: Wu, J.; Choi, J.; Won, C.; Wu, Y. Z.; Scholl, A.; Doran, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Near-Field Spectroscopy of Selectively Oxidized Vertical Cavity Surface Emitting Lasers

Description: Selectively oxidized vertical cavity surface emitting lasers (VCSELS) have been studied by spectrally resolved near field scanning optical microscopy (NSOM). We have obtained spatially and spectrally resolved images of both subthreshold emission and lasing emission from a selectively oxidized VCSEL operating at a wavelength of 850 nm. Below threshold, highly local high gain regions, emitting local intensity maxima within the active area, were observed; these were found to serve as lasing center… more
Date: December 9, 1999
Creator: Kim, J.; Boyd, J. T.; Jackson, Howard E. & Choquette, Kent D.
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Partner: UNT Libraries Government Documents Department
open access

CHEMISTRY OF SO{sub 2} ON MODEL METAL AND OXIDE CATALYSTS: PHOTOEMISSION AND XANES STUDIES

Description: High-resolution synchrotron based photoemission and x-ray absorption spectroscopy have been used to study the interaction of SO{sub 2} with a series of metals and oxides. The chemistry of SO{sub 2} on metal surfaces is rich. At low coverages, the molecule fully decomposes into atomic S and O. At large coverages, the formation of SO{sub 3} and SO{sub 4} takes place. The following sequence was found for the reactivity of the metals towards SO{sub 2}: Pt {approx} Rh < Ru < Mo << Zn, Sn… more
Date: July 9, 2000
Creator: Rodriguez, J. A.; Jirsak, T.; Chaturvedi, S.; Hrbek, J.; Freitag, A. & Larese, J. Z.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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