777. Electrical and photoelectric investigations on surfaces of copper phthalocyanine single crystals

777. Electrical and photoelectric investigations on surfaces of copper phthalocyanine single crystals

Classified abstracts 773-783 ionization potentials &rived from this work are in good agrccmcnt with recent photoelectron values. The results are di...

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773-783

ionization potentials &rived from this work are in good agrccmcnt with recent photoelectron values. The results are discussed in sonic detail. A Bendix Model 14-206 mass spectrometer, modified to include an RPD system and an ion lens in the time-of-flight tube, was used for the mass spectra1 measurements. G M Begun and R N Compton, J Chem Phys, 58 (6), 15 March 1973, 227 I-2280. 33 773. Molecular beam measurements of total collision cross-sections for HzO. (USA) The total cross-section for HZO-HZ0 scattering was measured with a supersonic nozzle beam system. This beam source could be operated over a wide range of temperatures and at pressures up to several atmospheres. The scattering chamber was maintained at pressures below Y lo-’ torr. The primary beam had a narrow velocity distribution and the velocity was varied by control of the nozzle temperature. Velocities were determined by time-of-flight techniques. The cross-sections for HZ0 are surprisingly small, e.g., 3.07 :.: IO-‘” IO’ cm/s. cm* at I W R Snow et al, J Chem fhys, 58 (6), I5 March 1973, 2517-2520. 33 774. Low-energy electron diffraction apparatus. (USSR) An arrangement of a LEED apparatus with two perpendicular electron guns and one fluorescent screen is described. This arrangement enables one to obtain LEED patterns on the fluorescent screen at practically all possible angles of the invesitgated sample with respect to the incident electron beam, which is advantageous in the observation and identification of micro-impurities by characteristic Auger peaks. The all-metal bakeable apparatus is evacuated to 2 \J 10m9 torr by an ion-getter pump. Energy of primary electrons can be varied between IO and 400 eV, the electron current between 1 and IO PA and the electron beam spot on the sample is less than I mm. V M Artemov et al, Prih Tekh Ekspw, No 2, March-April 1972, 234 (iff Russian), 33 775. Apparatus for investigating the kinetics of phase transitions in solids. (USSR) An experimental arrangement is described which is intended fol investigating the kinetics of thermally stimulated phase transitions in conducting solids. Phase transitions are observed with the aid of a contact-less ultrahigh frequency method in a waveguide evacuated to 10m3 torr. The method can also be used for investigation of phase transitions in vacuum evaporated thin films. V I Zaliva and V P Zakharov, Prib Tekh Eksprr, No 2, March- April 1972, 212.-214 (in Russian). 33 776. Structural investigations of crystal layers. (USSR) A vacuum method for investigating the structure of crystal surface layers is presented. The method is based on analysis of reflection electron diffraction from different parts of the plane of oblique cutting of the surface layer. The method can also be used for investigation of epitaxial films. G M Malkin et al, Prib Tekh Ek.cper, No 2, March-April 1972, 205-208 (in Russian). 33 777. Electrical and photoelectric investigations on surfaces of copper phthalocyanine single crystals. (Germany) Electrical and photoelectric properties of single crystal surfaces of copper phthalocyanine, carefully baked for some days under high vacuum conditions, are investigated. Evaporated gold contacts are used. Experimental results are discussed. C Hamann, Phys Star Sol (a), 10 (I), March 1972, 83-90. 33 778. Photon emission during bombardment of solids with alkali ions in the energy range between 2 and 10 keV. (Germany) Experimental results are reported regarding the emission of photons by solids bombarded with 2 to 10 keV alkali ions. The experimental arrangement is described. The vacuum chamber was evacuated down data on spatial and spectral to 5 i IO-” torr. The experimental distribution are interpreted with respect to a sputtering mechanism. In this process sputtered particles are excited and emitted by atomic collisions with the projectile ion. Outside of the solid in front of the surface the excited particles interact electronically with the surface and recombine radiatively into deeper electronic states. So the higher photon yields for insulators and semiconductors compared to metals 386

can be explained. An attempt wab made to intcrprct the spatial distribution of photon emission. H Kerkow, Phy.v S/d Sol (u). IO (2!. April 1972. 501 508. 33 779. Cathode heater unit. (USSR) An invention designed to increase the electrical resistance of the insulating layer between the cathode and heater of indirectly-heated valves and other electronic devices is described. Alundum metallized with nickel is used as insulating material, the proportion of nickel on the surface of the alundum grains being strictly regulated (0.5-0.7 wt. per cent). If the amount of nickel is reduced further, pool sintering takes place; if the amount of nickel is increased, the electrical resistance diminishes. Sintering is best carried out at 125O’C for 20 min. The nickel is best applied to the alundum by depositing its formate and then subjecting to heat treatment. G I Fridgant et al, USSR Patcwt No 322799, uppl 15th May 1970, prrhld 9th Frb 1972. 33 780. Method of manufacturing an impregnated cathode. (USSR) Difficulties arising in the conventional method of manufacturing impregnated cathodes are considered bricgy, some of the material goes into the wrong place, and it is also very hard to obtain an accurate estimate of the amounts of material impregnating the cathode, as a number of time-comsuming measurements are required. The situation may be ameliorated by using a special reservoir (a hollow cylinder made of refractory material) placed on the surface of the porous recipient material at the time of impregnation and afterwards removed. The porous material and the reservoir are heated together (for example, to 18OO’C when the impregnating substance is barium aluminate), the heating period being determined empirically in each particular case. After cooling, the surface is cleaned and polished. E G Komogortseva and F F Manukhin, USSR Patcut No 325645. appl 19th May 1970, pub/d 14th March 1972. 33 781. Tube with point field emission cathode for producing nanosecond pulses of fast electrons. (USSR) A sealed glass two-electrode electron tube with a field emission point cathode is described. At an amplitude of 150 kV of accelerating per pulse voltage with a slope of IO IL V/s , a flow of IO’” electrons is produced on the external side of the beryllium window, with duration of a few nanoseconds. At this high slope of voltage pulse the vacuum gap withstands considerable overvoltage, and at residual gas pressures in the range of 1O-‘Z to IO-’ torr, the developing high-voltage breakdown initiated by field emission of electrons, does not change into an arc stage. After single pulse operation for a year, the tube withstands over IO” pulses without substantial change in its characteristics. The dose at the output window is 40 krad/pulse. N G Pavlovskaya and T V Kudryatseva, Prih Tekh Ekspw, No 2, March&April 1972, 198-201 (it7 Rumian). 33 782. Negative ion source (USSR) A source of negative ions is described which utilizes the emission of negative ions by bambardment of certain solid surfaces by positive alkali ions. Alkali halogen salt is evaporated from a heated crucible and the molecules are dissociated on a heated filament. Accelerated positive alkali ions bombard the target and sputtering process takes place at which negative ions are produced. Using the described source in combination with a mass analyzer, stable beams of negative ions of Cu, Ag, Au, C, 0, Cl and some hydrocarbons have been obtained with intensities of IO-” to IO-’ A. A Kh Ayukhanov and V N Chernenko, Prih Tekh Ekspw. No 2, March&April 1972, 150-I 5 I (in Russiutz). 33 783. Etiiciency of ion focusing intensive electron beams with short duration. (USSR) The possibility of ion focusing electron beams, with current of 300 A in pulses at a voltage of 100 kV and pulse length of 0.12 psec, is investigated. A pressed matrix oxide-nickel (BN) cathode with a diameter of 50 mm was used as electron emitter. It is shown that efficient ion focusing of the electron beam with the mentioned duration occurs in the pressure range of 5 :s IO-” to 1.3 IO-’ torr. Efficiency of ion focusing is considerably reduced in the pressure emission does not range of 5 > 10e4 to 1 i- 10e3 torr. Cathode IO-” to 1.3 10e2 torr. decrease in the pressure range of 5