Barry Petersen - Academia.edu (original) (raw)

Papers by Barry Petersen

$Research paper thumbnail of Toward a surface photoelectron diffractometer: A progress report on selected advances and an assessment$

Journal of Electron Spectroscopy and Related Phenomena, May 1, 1994

This document was prepared as an account of work sponsored by an agency of the United States Gove... more This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of an_ information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of Calift, rnia. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes.

Applied Physics A, Mar 1, 1998

We report on the fabrication of Gd nanowires studied by in-situ scanning tunneling microscopy (ST... more We report on the fabrication of Gd nanowires studied by in-situ scanning tunneling microscopy (STM). Gd wires of monoatomic height and a few nanometers width are stabilized on W(110) along the surface steps upon annealing of a sub-monolayer Gd film at 1100 K. At 1200 K, diffusion of Gd islands into the W(110) surface layer is observed. Scanning tunneling spectroscopy data of the Gd wires reveals an image-potential state at ∼ = 3.2 eV above the Fermi energy, which is used to obtain large element-specific contrast in the STM images.

Journal of Electron Spectroscopy and Related Phenomena, Dec 1, 1995

ABSTRACT A multiple-wavenumber analysis method for scanned-angle photoelectron holography is refi... more ABSTRACT A multiple-wavenumber analysis method for scanned-angle photoelectron holography is refined to image the near-surface atoms at a Cu(001) crystal face. The atoms one layer above the emitter are imaged at the appropriate location although shifted by 0.2Å. To strengthen this analysis, a comparison is made with a simple model which gives a similar result. A theoretical study is also presented that demonstrates why a holographic analysis scheme for scanned-angle diffraction patterns tends to preferentially image forward scattering atoms unlike scanned-energy variants of holographic atom imaging.

Journal of Organic Chemistry, May 1, 1990

Table 11. Chlorides from Alcohols Using PPTC PLPCI' ROH RCl R conditions % yield n-hexyl 25 "C, 6... more Table 11. Chlorides from Alcohols Using PPTC PLPCI' ROH RCl R conditions % yield n-hexyl 25 "C, 6 h benzyl 25 "C, 6 h s-pentyl 50 "C, 12 h i-pentyl 25 "C, 12 h neopentyl 25 "C, 1 2 h (R)-(-)-Z-octyl 25 "C, 5 min tert-butyl 50 "C, 1 2 h norbornyl 25 "C, 1 2 h cyclopropylmethyl 0 "C, 5 min 77 100 80 44 55 85 (94% ee inversion) 97 60 98 distilled to give the desired product in good yield (Table 11). With this discovery, we have broadened the scope of reactivity of PPTC. We feel that continued studies on PPTC itself and other similar organophosphorus compounds could potentially contribute a variety of new synthetic methodologies to the organic chemist. Experimental Section All products were identified by comparison to authentic samples. A typical procedure is given for the preparations of the aryl chlorides listed in Table I. The chlorides listed in Table I1 were prepared in the same manner using the conditions specified in Table 11. General Procedure. Chlorine gas (10 g, 142 mM) is bubbled into phenylphosphorus dichloride (18.6 mL, 142 mM) a t such a rate as to maintain the reaction temperature at 70-80 "C. After the chlorine addition is complete, the resulting molten PPTC is a clear yellow liquid. Phenol (13.4 g, 142 mM) is added on one portion, and the reaction mixture is heated to 160 "C overnight. The cooled reaction mixture is then poured onto crushed ice/water (200 mL) and neutralized with 50% aqueous sodium hydroxide. After extraction with ether, the combined ether extracts are dried and distilled to give chlorobenzene (12.1 g, 76%) as a colorless liquid.

Chemical Physics Letters, Mar 1, 1994

... Panels A, C and E show symmetryaveraged emission patterns of platinum 4fs/i photoelectron int... more ... Panels A, C and E show symmetryaveraged emission patterns of platinum 4fs/i photoelectron intensity after background removal and Fourier filtering, measured at k-9.0, 9.8, and 10.2 A-` (309, 366 and 396 eV), respectively. ... [22] JJ Barton, J. Electron ... [23] DJ Friedman and CS ...

Physical Review A, Jun 1, 1994

The study of photoelectron satellites in the near-threshold region is important for differentiati... more The study of photoelectron satellites in the near-threshold region is important for differentiating among various electron correlation mechanisms. For CO, which is a prominent test case for theories describing electron correlation effects, the threshold and near-threshold branching ratios (BR s) of the K-shell satellites were measured. Eight different C 1s satellite states were identified, showing very complex threshold behavior. The resonancelike behavior of the {20.) '(1n.) '(2~)'(5'=1) satellite BR agrees with recent theoretical calculations. The observed energy dependence of the singlet (2o.) '(1m) '(2m. *)' satellite compares less well with the calculations. Three X+ satellites with a (2o.) '(50) '(no.)' configuration have a constant satellite BR over the energy range studied. Three 20. satellites, which have been assigned as pure conjugate shake-up states, have intensity only near threshold. The threshold spectrum above the 0 1s ionization threshold consists of two distinct groups of satellites. Conjugate shake-up transitions contribute to the intense feature centered at 551-eV binding energy, which is not observed above its threshold. Two 'X+ satellites, which have been described by configuration interaction of (1') '(50.) '(no.)' states with a singlet mm. * state, show indications of shape-resonance-like behavior.

Chemical Physics Letters, Oct 1, 1993

A 351 eV photoelectron hologram of a Pt (11 I) surface was collected by detection of photoelectro... more A 351 eV photoelectron hologram of a Pt (11 I) surface was collected by detection of photoelectrons from the 4fs,, subshell in a display analyzer, and was Fourier-analyzed. The real space image showed sensitivity to the fourth atomic layer, excellent reproduction of the fee lattice, and sixteen source-atom neighbors. Transverse atomic positions were located to 0.1 A. Photoelectron holography is thus shown to be capable of imaging lattices and interfaces, using low-energy electrons.

Journal of the American Chemical Society, Aug 1, 1989

Table 1. Vibrational Frequencies for Dioxygen-Bound Complexes' v(Fe-0). cm-' ref cytochrome oxidase

MRS Proceedings, 1994

Thisis a preprintof apaperintendedforpublication in ajournalorproceedings. Since changes may be m... more Thisis a preprintof apaperintendedforpublication in ajournalorproceedings. Since changes may be made before publication, this preprintis made available with the understandingthat it will not be cited orreproducedwithout the permission of the author. MASTE/ Ir, frRl_OTlOfl OFTHiSOOCRMENT [$[J_i_[IJ_O o DISCLAIMER This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responslbilitT for the accuracy, completeness, or usefulness of any information, apparatus, prod_m, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Governlaent or the University of California. The views and opinions of authors expr_sed herein do not necessarily state or reflect those of the United States Government or the University of California, and shah not be used for advertising or product endorsement purposes.

Bulletin of the American Physical Society, May 1, 1993

We have recently studied the threshold behavior of the K-shell photoelectron satellite/main line ... more We have recently studied the threshold behavior of the K-shell photoelectron satellite/main line branching ratios in CO with high-resolution photoelectron spectroscopy and zero electron kinetic energy (ZEKE) spectroscopy. The electron time-of-flight measurements were performed at the Stanford Synchrotron Radiation Laboratory with a spherical grating monochromator. The ZEKE spectra above the Cls and Ols ionization thresholds show remarkable differences in the

Journal of Microscopy, May 1, 1999

We report on the combination of a scanning near-®eld optical microscope and a modi®ed Sagnac inte... more We report on the combination of a scanning near-®eld optical microscope and a modi®ed Sagnac interferometer for magnetic-domain imaging in the re¯ection mode. The Sagnac interferometer is used for detection of the magnetooptical Kerr effect. Since the interferometer is inherently insensitive to polarization changes caused by topography effects, magnetic-domain imaging is not limited to samples with¯at surfaces. In this way, it is possible to image magnetic bits written on the tracks of a magneto-optical disc that has a rather pronounced surface pro®le.

MRS Proceedings, 1993

Platinum atoms near a (111) single-crystal face have been imaged using photoelectron holography. ... more Platinum atoms near a (111) single-crystal face have been imaged using photoelectron holography. Electron angular intensity patterns were collected at equally spaced wavenumbers from 6A-l to 12A-l. Images of atoms near expeCted atomic positions are obtained from singlewavenumber analyses over the range of the data set. Positions are detected further from the emitter than we have seen previously, and we have also adopted a three dimensional means of representing the data in order to help understand the results. Twin image suppression and artifact reduction in the holographically reconstructed data set are ob~ed when images at different wavenumbers are correctly phase-summed. We are assessing the capability of the technique for rendering true three-dimensional structural infonnation for ~own systems.

J Org Chem, 1990

... (1) Yannoni, C. S.; Kendrick, RDJ Chem. Phys. 1981, 74,747. (b) Horne, D.; Kendrick, RD; Yann... more ... (1) Yannoni, C. S.; Kendrick, RDJ Chem. Phys. 1981, 74,747. (b) Horne, D.; Kendrick, RD; Yannoni, C. S. J. Magn. Reson. 1983,52,299. (2) (a) Yannoni, CS; Clarke, TC Phys. Rev. Lett. 1983,51, 1191. (b) Clarke, TC; Yannoni, CS; Katz, TJ J. Am. Chem. SOC. 1983,105, 7787. ...

Journal of the American Chemical Society, 1989

... (5) (a) Yannoni, CS; Kendrick, RD J. Chem. Phys. 1981, 74,747. (b) Horne, D.;Kendrick, R. D.;... more ... (5) (a) Yannoni, CS; Kendrick, RD J. Chem. Phys. 1981, 74,747. (b) Horne, D.;Kendrick, R. D.; Yannoni, C. S. J . Magn. Reson. 1983, 52, 299. (6) See: Myhre, PC; Yannoni, C. S. J. Am. Chem. SOC. 1981, 103,230. Samples ...