Kenneth Charles Hass, a theoretical condensed matter physicist, died on 1 June 2005 in Ann Arbor, Michigan, after a long, courageous, and graceful bout with cancer. At the time of his death, he led 60 physicists, chemists, and engineers as manager of the physical and environmental sciences department at the Ford Motor Co.Ken was born in Flushing, New York, on 7 May 1958 and attended Queens College, where he earned a BA, summa cum laude, in physics and mathematics in 1979. He attended graduate school at Harvard University under an NSF graduate fellowship and received an AM in 1980 in physics and a PhD in theoretical solid-state physics in 1984. His thesis adviser, Henry Ehrenreich, remembers Ken as one of his “most broadly interested and imaginative graduate students, whose friendliness, helpfulness, and modesty were inspiring to anyone who had the privilege of working with him.” Ken held joint appointments as a postdoctoral fellow at Harvard and a visiting scientist at MIT before joining Ford’s Scientific Research Laboratory in 1987.Initially Ken’s research focused on the effects of disorder in semiconductor alloys, the electronic structure and magnetic properties of diluted magnetic semiconductors, the electronic properties of copper oxide-based high-T c. superconductors, and the vibrational and thermal-transport properties of isotopically modified diamond. Among the dozens of papers he wrote on these subjects, his 1989 chapter “Electronic Structure of Copper-Oxide Superconductors” in Solid State Physics certainly stands out as a seminal publication.Ken made theoretical contributions to many Ford projects. The most significant work from a scientific and societal perspective was his groundbreaking density functional theory studies of the adsorption and catalysis of nitrogen oxides (NO x ) on metals, zeolites, and oxides and of the bulk and surface structures and hydration of aluminas. Those issues are central to air-quality improvement technologies, including automotive emission controls.In 2001, Ken became the manager of the chemical and environmental sciences department, and beginning in 2002, he led the organization formed by its merger with the physics department. Ken responded to the challenging times in the automotive industry by arguing successfully that critical research areas such as environment, energy, safety, and new materials demanded long-term support from Ford.Ken was equally at home in the academic and corporate worlds. He had a lifelong interest in science education. While leading a strong materials-modeling effort at Ford, he simultaneously served on the American Physical Society’s committee on education (1998-2000), including one year as its chair. Ken worked tirelessly to promote and expand the activities of the APS forum on industrial and applied physics during his tenure as vice chair, chair, and past chair (2001-04). He wrote and spoke eloquently of the need for new approaches and attitudes in industrial research and academia. Ken was elected an APS fellow in 2004 in recognition of his significant applications of atomic-level modeling to technological materials and his outstanding leadership in the promotion of industrially relevant research and education. A yearlong sabbatical (1999-2000) in the physics department at the University of Michigan, Ann Arbor, enabled Ken to explore ideas from the emerging field of complexity. On returning to Ford, he applied the new ideas to technical management and other complex problems. Working closely with the Center for Complex Systems at Michigan, he encouraged applications of this discipline to practical problems such as sustainable mobility.An avid reader, Ken appreciated the complementary approaches of scientific reductionism and the view that fundamental laws exist at all levels of the physical world. He thought seriously about the roles of science and religion. His personal interests included travel, food and wine, chess, tennis, and music.Those in the physics community who read Ken’s papers or heard him speak will remember him as a first-rate scientist. Those at Ford can also attest that he was a leader who possessed outstanding vision and integrity. He was a terrific colleague and friend, and we all miss him. Kenneth Charles Hass JIM BRETZ, FORD MOTOR COPPT|High resolution© 2005 American Institute of Physics.

Micro-Raman spectroscopy has been widely used to measure local stresses in silicon and other cubic materials. However, a single (scalar) line position measurement cannot determine the complete stress state unless it has a very simple form such as uniaxial. Previously published micro-Raman strategies designed to determine additional elements of the stress tensor take advantage of the polarization and intensity of the Raman-scattered light, but these strategies have not been validated experimentally. In this work, we test one such stategy [S. Narayanan, S. Kalidindi, and L. Schadler, J. Appl. Phys. 82, 2595 (1997)] for rectangular (110)- and (111)-orientated silicon wafers. The wafers are subjected to a bending stress using a custom-designed apparatus, and the state of (plane) stress is modeled with ABAQUS. The Raman shifts are calculated using previously published values for silicon phonon deformation potentials. The experimentally measured values for σxx, σyy, and τxy at the silicon surface are in good agreement with those calculated with the ABAQUS model.

In situ Raman experiments excited with 244 nm radiation are carried out on Pt/γ-Al2O3 and Pt/Ba/γ-Al2O3 catalysts. The addition of Ba allows the normal catalyst to store substantial amounts of NOx as Ba nitrates under lean burn conditions. Dilute amounts of NO and/or SO2 plus O2 in N2 are flowed over the catalysts, with the temperatures and concentrations chosen to simulate the NOx trapping and sulfur poisoning characteristics encountered in normal operation. Adsorbed species observed on Pt/γ-Al2O3 are nitrite/nitro species and sulfate on γ-Al2O3 and NO on Pt. On Pt/Ba/γ-Al2O3, in situ UV Raman spectra showed typical NOx trap behavior:  NOx and SOx are stored as Ba(NO3)2 and BaSO4 during lean conditions and released at higher temperatures in H2 flow. Prolonged SO2 exposure eventually deactivates the catalyst for NOx storage. The sulfate purged by heating to 500 °C in H2 is not completely removed from the catalyst, since it can reappear at lower temperature without additional exposure to SO2. On both Pt/γ-...

A new pale blue corrosion product has been found on copper alloy artifacts in the collections of a number of institutions. The corrosion product has been characterized using X-ray powder diffraction, X-ray photoelectron spectroscopy, wavelength X-ray dispersive spectroscopy and Raman microspectroscopy. The corrosion product is a copper(II) compound, containing copper and sodium in a ratio of approximately 1:1 along with formate and acetate groups. It is speculated that formic (methanoic) and acetic (ethanoic) acid vapors arising from materials used to house the objects contribute to the formation of this compound.

Raman spectra of SOx adsorbed on γ-alumina and Pt/γ-alumina model catalysts have been obtained with a 244 nm Raman spectrometer. Strong peaks in the 980–1380 cm-1 region characteristic of adsorbed sulfates are clearly portrayed in the spectra, which contrast with fluorescence-dominated scans obtained using visible excitation. Broad bands are also observed in the 3500–3700 cm-1 O–H stretch region on the γ-alumina, which belong to weakly-bound physisorbed water and more strongly-bound surface hydroxyls. These features are monitored as the samples are heated up to 600°C in the presence of nitrogen. The sulfate peaks vary in position depending on whether or not the γ-alumina is loaded with platinum, hydrated, or dehydrated. Platinum appears to inhibit the physisorption of water and the formation of hydroxyls on the γ-alumina surface, as evidenced by the absence of O–H stretch vibrations on the Pt-loaded sample. Our spectral data demonstrate that UV Raman spectroscopy is a useful technique for analytical studies of adsorbed SOx on γ-alumina, and holds promise for future in situ investigations of other adsorbed species on catalytic substrates of automotive interest.

Measurements of NO concentrations at sub-ppm levels in vehicle exhaust are needed for emissions certification of future ultra-low emission vehicles. We demonstrate a wavelength-modulation, laser-based, NO detection system suitable for this purpose. A quantum cascade distributed feedback laser (QC-DFB) operating continuous wave (cw) at ∼100 K is frequency modulated at f = 10 kHz and locked to the center of a transition at ∼1921 cm−1 in the fundamental band of NO. The demodulated signal at 2 f of the beam passing through the sample cell directly measures the NO concentration. The cell is a multipass Herriott-type with a 100-m path length. Doppler broadening, pressure broadening, and unresolved Λ doubling combine to yield a pressure for optimum sensitivity of 100 torr and a modulation amplitude of ∼600 MHz. A flowing gas system is used to avoid problems with adsorption and desorption of NO from the cell walls. The reduced pressure eliminates interference from other gas species. Detection of NO concentrations in the few parts-per-billion (ppb) range is demonstrated in diluted exhaust-gas bag samples collected in the vehicle certification process.

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A model automotive-exhaust catalyst, Pd on Zr-rich ceria–zirconia, was characterized by X-ray diffraction, optical and electron microscopies, and micro-Raman spectroscopy following high-temperature aging. A broad bimodal distribution of Pd, introduced amongst the 10-μ m spherical particles of support material during catalyst preparation, was found to persist upon aging, and strained PdO was detected predominantly in those particles containing the higher concentration of Pd. The strain, approximately -1% by volume, was determined from the shift of the strong PdO Raman line at 650 cm-1 and the Grüneisen parameter, which was measured in a separate experiment in a diamond-anvil cell. The origin of the compressive stress that gives rise to this strain is believed to be the same as in the previously known phenomenon of Pd–metal encapsulation, but the Pd particles involved here are apparently not highly constrained within the sintered ceria–zirconia matrix prior to their oxidation.

We describe a prototype night vision system for automotive applications that uses a high power near-infrared (NIR) diode laser, compact optics, and a CCD camera. Because NIR radiation is invisible to the human eye, a high-beam illumination pattern can be formed permitting a clear view of objects on both sides of the roadway, even in the presence of oncoming traffic. A narrow band-pass filter in front of the camera passes only the laser wavelength and prevents blooming of the image due to the headlights of other vehicles. This system permits drivers to see objects at night (such as debris or pedestrians) that are in close proximity to oncoming vehicles. The diode laser operates at 810 nm and emits 5 - 10 W. The illuminator distributes the laser light using a combination of refractive, reflective, and holographic optics in a manner that meets the standards for Maximum Permissible Exposure. We discuss the performance of our prototype system as a function of laser power and camera field-of-view and sensitivity, and we provide comparisons with a commercially available automotive night-vision system that uses a thermal-imaging camera.

Raman scattering is a powerful technique for studying catalysts used in the treatment of automotive exhaust gas. It has the sensitivity and chemical specificity needed to identify the oxide phases of many of the precious metals (Pt, Pd, Rh) used in these catalysts, even when they are highly dispersed on high-surface-area supports such as (gamma) -Al2O3. Moreover, this technique can be employed in situ under temperature (300 - 600 degree(s)C) and pressure (1 atm) conditions typically encountered in normal operation. Bulk Pd oxide (PdO) is readily detected with visible excitation, because of a strong resonance Raman enhancement, and its formation and decomposition on Pd/(gamma) -Al2O3 and Pd/ZrO2 catalysts can be followed in real time. Pt does not oxidize as easily as Pd, but a layer of atomic O will form on Pt, and it produces a Raman signature that can be detected with UV excitation at 244 nm. Similarly, UV excitation enhances spectra from adsorbed NOx and SOx and hydroxyls on model Pt/(gamma) -Al2O3 catalysts. In situ UV Raman spectra of Ba-containing catalysts, being considered for use as NOx traps, show adsorbed NOx and SOx and, thus, can be used to characterize the NOx trapping, S poisoning, and regeneration of the trap. UV excitation has several advantages in addition to the eletronic resonance enhancment: the signal is increased because of the dependence of the Raman cross section on the fourth power of the frequency, the fluorescence is often Stokes shifted well beyond the range of the Raman lines, and the thermal background from a heated sample is negligible.