The formation of defect centers in MgO
Defect F centers formation in MgO, discussing optical absorption bands, oscillator strengths, luminescence band, impurity centers, etc
Kroes, R. L.↗
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Opaque minerals and olivine in lavas and breccias from Mare Tranquillitatis
Apollo 11 lunar rock lavas and breccias, examining opaque minerals and olivine by reflection microscopy, electron probe and optical absorption measurements
Bell, P. M.↗
Electron beam pumped laser action in selenium and tellurium with applications for tunable backward parametric oscillations Final report
Growth of selenium and selenium-tellurium alloy crystals with determination of optical absorption and photoconductivity
Source record↗
Electron paramagnetic resonance of V/2 plus/, Mn/2 plus/, Fe/3 plus/, and optical spectra of V/3 plus/ in blue zoisite, Ca2Al3Si3O12/OH/
Electron paramagnetic resonance and optical absorption spectra of transition metal ions in zoisite crystal
Ghose, S.↗
Hydrogen defects in proton bombarded KCl.
Optical absorption bands are observed in the UV and IR proton bombarded potassium chloride at liquid nitrogen temperature. It is demonstrated that the absorption is due to trapped protons, and the largest UV band has been identified with the U center.
Chu, Y. H.↗
Solid state image sensing arrays
The fabrication of a photodiode transistor image sensor array in silicon, and tests on individual elements of the array are described along with design for a scanning system for an image sensor array. The spectral response of p-n junctions was used as a technique for studying the optical-absorption edge in silicon. Heterojunction structures of Sb2S3- Si were fabricated and a system for measuring C-V curves on MOS structures was built.
Sadasiv, G.↗
The reaction of H2O2 with NO2 and NO
The reactions of NO and NO2 with H2O2 have been examined at 25 C. Reaction mixtures were monitored by continuously bleeding through a pinhole into a monopole mass spectrometer. NO2 was also monitored by its optical absorption in the visible part of the spectrum. Reaction mixtures containing initially 1.5 - 2.5 torr of NO2 and 0.8 - 1.4 torr of H2O2 or 1 - 12 torr of NO and 0.5 - 1.5 torr of H2O2 were studied. The H2O2 - NO reaction was complex. There was an induction period followed by a marked acceleration in reactant removal. The final products of the reaction, NO2, probably H2O, and possibly HONO2 were produced mainly after all the H2O2 was removed. The HONO intermediate was shown to disproportionate to NO2 + NO + H2O in a relatively slow first order reaction. The acceleration in H2O2 removal after the NO - H2O2 reaction is started is caused by NO2 catalysis.
Gray, D.↗
Ultraviolet and charged particle irradiation of proposed solar cell coverslide materials and conductive coatings for the Helios spacecraft
Coverslide materials consisting of Corning 7940 fused silica, multilayers of titanium and manganese oxides (blue reflector), and indium oxide (conductive-coating) were exposed to 16 UVSC up to 800 EUVSH in vacuum. Slight changes in optical transmittance and optical absorptance were found in the (200-360) millimicron regions of the fused silica and conductive coating respectively. Exposure to 4 KeV protons and 4.5 KeV electrons in vacuum, produced decreases of several percent in transmittance, (200-360) millimicron region in the fused silicas after total fluxes less or = 10 to the 14th power particles/sq cm. Sheet resistance of the conductive coating increased above 1.0 kilo-ohm/square after a total flux less or = 10 to the 14th power particles/sq cm. Solar cells with coverglasses utilizing the indium oxide conductive coating were exposed to 1 Mev electrons and 1 Mev protons in air and in vacuum. Total fluxes ranged from 10 to the 11th power particles/sq cm to 10 to the 15th power particle/sq cm. There was no appreciable degradation in the resistance of the conductive coating during or after these tests.
Fry, J.↗
Experimental observation of Wannier levels in semi-insulating gallium arsenide.
Optical absorption in an electric field has been of increased interest in recent years since Callaway predicted that the Wannier levels may be observable in direct-transition semiconductors such as GaAs. In this work, such levels have been observed for the first time and found to be in substantial agreement with the Callaway theory.
Koss, R. W.↗
Instrumentation for air quality measurements.
Comparison of the new generation of air quality monitoring instruments with some more traditional methods. The first generation of air quality measurement instruments, based on the use of oxidant coulometric cells, nitrogen oxide colorimetry, carbon monoxide infrared analyzers, and other types of detectors, is compared with new techniques now coming into wide use in the air monitoring field and involving the use of chemiluminescent reactions, optical absorption detectors, a refinement of the carbon monoxide infrared analyzer, electrochemical cells based on solid electrolytes, and laser detectors.
Loewenstein, M.↗
Ammonium perchlorate gasification and combustion at high heating rates and low pressures.
Mass-spectrometric and linear regression rate characterizations are reported, derived from CO2 laser pyrolyses of pressed NH2ClO4 (AP) at incident heat fluxes ranging from 25 to 4000 cal/sq cm sec. Product evolution-rate histories were obtained in vacuo by time-resolved (5 msec) mass spectrometry during (1) transient heat-up, and (2) subsequent quasi-steady vaporization (QSV). Vaporization induction times were obtained for (1); these, coupled with heat-transfer approximations neglecting thermochemical heat release, indicated that optical absorption at 10.6 microns dominated over conduction for heat fluxes much greater than 300. Conclusions applying in vacuo were: preferential desorption of NH3, with net accumulation of adsorbed HClO4, occurred during transient heat-up and onset of condensed phase decomposition (CPD), but preferential decomposition of adsorbed HClO4 (compared to NH3) occurred during QSV when CPD was significant. CPD was the dominant mode of QSV at moderate heat fluxes.
Pellett, G. L.↗
Red clouds in reducing atmospheres
A dark reddish-brown high-molecular weight polymer is produced by long wavelength ultraviolet irradiation of abundant gases in reducing planetary atmospheres. The polymer is examined by paper chromatography, mass spectrometry, and infrared, visible, and ultraviolet spectroscopy. High carbon-number straight-chain alkanes with NH2 and, probably, OH and C = O groups are identified, along with amino acids. There are chemical similarities between this polymer and organic compounds recovered from carbonaceous chondrites and precambrian sediments. The visible and near-ultraviolet transmission spectrum of the polymer shows its absorption optical depth to be redder than lambda(-2) and perhaps similar in coloration to the clouds of Jupiter, Saturn, and Titan. The nitrile content is small, and the polymer should be semitransparent in the 5 micrometer atmospheric window. Such polymers may be a common constituent of clouds in the outer solar system and on the early earth.
Khare, B. N.↗
Physics of compact nonthermal sources. II Determination of physical parameters
A set of restrictions upon the magnetic field and visible angular size of a canonical nonthermal source (one whose emission is incoherent electron synchrotron) has been obtained in another paper. The degree of electron anisotropy and magnetic field disordering were left as free parameters. In the present paper these restrictions are applied to the variable compact radio sources 3C 84, 3C 120, 3C 273, 3C 279, 3C 454.3, CTA 102, 3C 446, PKS 2134 + 004, VRO 42.22.01, and OJ 287. The theoretically derived angular sizes for these sources are in reasonable agreement with published VLBI sizes, provided that the characteristic pitch angles are not extremely small. The magnetic field strengths determined from the degree of circular polarization are generally compatible with field strengths derived from the self-absorption and synchrotron self-Compton conditions, again provided that the pitch angles are not too small. It is argued that the self-absorption optical depth cannot be much less than unity near the low-frequency turnovers; otherwise, serious discrepancies with observation result.
Jones, T. W.↗
Interstellar molecular abundances toward omicron Persei
Extensive scanning of the B1 III star omicron Per has been done with the Copernicus telescope-spectrometer in an effort to determine column densities or meaningful upper limits for several molecules expected to be relatively abundant in H I regions of moderate density. The combination of radio H II, OH, and CO emission-line data with the optical absorption measurements indicates that omicron Per is embedded in the near edge of a dense molecular cloud and that the material seen in front of the star must be close to it. Molecules detected in ultraviolet absorption are H2, HD, CO, and possibly OH. The CO rotational temperature is between 2.2 and 3.8 K. The observed column densities and upper limits from Copernicus and ground-based data are compared with recent models for molecular formation in diffuse clouds.
Snow, T. P., Jr.↗
Characterization of iron-doped lithium niobate for holographic storage applications
A comprehensive characterization of chemical and holographic properties of eight systematically chosen Fe:LiNbO3 crystals is performed in order to determine optimum performance of the crystals in holographic storage and display applications. The discussion covers determination of Fe(2+) and Fe(3+) ion concentrations in Fe:LiNbO3 system from optical absorption and EPR measurements; establishment of the relation between the photorefractive sensitivity of Fe(2+) and Fe(3+) concentrations; study of the spectral dependence, the effect of oxygen annealing, and of other impurities on the photorefractive sensitivity; analysis of the diffraction efficiency curves for different crystals and corresponding sensitivities with the dynamic theory of hologram formation; and determination of the bulk photovoltaic fields as a function of Fe(2+) concentrations. In addition to the absolute Fe(2+) concentration, the relative concentrations of Fe(2+) and Fe(3+) ions are also important in determining the photorefractive sensitivity. There exists an optimal set of crystal characteristics for which the photorefractive sensitivity is most favorable.
Shah, R. R.↗
The photochemical cycle of bacteriorhodopsin
The reaction cycle of bacteriorhodopsin in the purple membrane isolated from Halobacterium halobium has been studied by optical absorption spectroscopy using low-temperature and flash kinetic techniques. After absorption of light, bacteriorhodopsin passes through at least five distinct intermediates. The temperature and pH dependence of the absorbance changes suggests that branch points and/or reversible steps exist in this cycle. Flash spectroscopy in the presence of a pH-indicating dye shows that the transient release of a proton accompanies the photoreaction cycle. The proton release occurs from the exterior and the uptake is on the cytoplasmic side of the membrane, as required by the function of bacteriorhodopsin as a light-driven proton pump. Proton translocating steps connecting release and uptake are indicated by deuterium isotope effects on the kinetics of the cycle. The rapid decay of a light-induced linear dichroism shows that a chromophore orientation change occurs during the reaction cycle.
Lozier, R. H.↗
Measurements of copper ground-state and metastable level population densities in a copper-chloride laser
The population densities of both the ground and the 2D(5/2) metastable states of copper atoms in a double-pulsed copper-chloride laser are correlated with laser energy as a function of time after the dissociation current pulse. Time-resolved density variations of the ground and excited copper atoms were derived from measurements of optical absorption at 324.7 and 510.6 nm, respectively, over a wide range of operating conditions in laser tubes with diameters of 4 to 40 mm. The minimum delay between the two current pulses at which lasing was observed is shown to be a function of the initial density and subsequent decay of the metastable state. Similarly, the maximum delay is shown to be a function of the initial density and decay of the ground state.
Nerheim, N. M.↗
Formulation of electrically conductive thermal-control coatings
The development and formulation of electrically conductive thermal control coating was undertaken for use on the International Sun Earth Explorer spacecraft. The primary effort was to develop a coating with a bulk resistivity of less than 100,000 ohm/sqm, an optical absorptance of approximately 0.55, and a normal emittance of 0.90. The required stability in space called for a bulk resistivity of less than 100,000 ohm/sq m, an absorptance of less than 0.67, and a normal emittance of 0.90 after exposure to approximately 4 x 10 to the 16th proton/sq cm of solar-wind particles and 5300 equivalent sun-hours. These exposures represent 2 years of ISEE flight conditions. Both the unsuccessful formulation efforts and the successful use of oxide pigments fired at 1448 K are described. Problems relative to the reactivity of specific coating vehicles exposed to high humidity are discussed.
Shai, M. C.↗