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1444. Structure of carbon monoxide chemisorbed on platinum
Classified abstracts 1441-1618 Classified abstracts 1441-1451 on this page
Editor's note The/abe/immediately following the title of each item denotes country or origin o[ publication, and that at the end of each abstract indicates country of origin of work (where known).
I. General v a c u u m science and engineering 14. KINETIC THEORY OF GASES 14 1441. Electric field influence on the thermodiffusion constant of gases. (USSR) Variation of the thermodiffusion constant of the gas mixtures NF3-Ar and C1~O-C180 due to electric field is observed experimentally at pressures from 28 to 58 torr. The experiments are carried out with a pulsing divider. The causes of the effect are considered. V D Borman et al, Zh Eksper Teor Fiz, 60 (5), May 1971, 1627-1629
(in Russian). 16. GASES AND SOLIDS 16 1442. Desorption spectrometry of gases with molecular sieves. I. Theoretical assumptions and measuring equipment. (Germany) Work by other authors on the flash-filament method has suggested the application of their theory to the slow desorption of gases from molecular sieves. This theory and the experimental equipment employed is described. A sample is introduced into a vacuum oven with controlled heating and the desorbed gases are analyzed by mass spectrometer after passage through a suitable system of vacuum and gas inlets. M Durra and K Starke, Vakuum-Technik, 20 (5), July 1971, 129-135
(in German). 16 1443. Gaseous self-diffusion through a porous medium. (USA) The mean free path theory of self-diffusion of "tagged "molecules is formulated for arbitrary Knudsen number in terms of two coupled integral equations. A variational upper bound on the net rate of diffusion through a porous slab is derived. W Strieder, J Chem Phys, 54 (9), 1st May 1971, 4050~053. 16 1444. Structure of carbon monoxide chemisorbed on platinum. (USA) C-O stretching frequencies for 1~C160,13C~60 and 12ClsO chemisorbed on silica supported platinum at 25 ° and 200 ° are used to demonstrate that the bonding to the surface is via the carbon atom. Empirical force constant correlations suggest that the best single structure approximation is Pt = C = O. K C Lin et al, J Chem Phys, 55 (3), 1st August 1971, 1148-1151. 16 1445. Influence of ion bombardment on the physical properties of semiconductors. (USSR) Influence of bombardment by relatively slow ions (energies up to 100 keV) on semiconducting materials is considered. Types of structural defects and investigational methods together with some results are described. The investigation of radiation defects by means of the angular dependence of secondary electron emission is described. Change in the electrical properties of semiconductors due to ion bombardment is studied in detail. Advantages of ion implantation of semiconductors are discussed. Results of investigations on the electrical conductivity of ion implanted layers and its variation during annealing are reviewed. Data on influence of ion bombardment on the behaviour of non-equilibrium charge carriers, radiation conductivity, and luminescence, are presented. Variation of the optical properties of semiconductors due to ion bombardment is also discussed. Influence of ion bombardment on impurity diffusion and the chemical activity of materials is studied. It is concluded that, with the aid of ion bombardment, materials may be produced with properties such as cannot be obtained by other techniques. I A Abroyan, Usp Fiz Nauk, 104 (1), May 1971, 15-50 (in Russian).
16 1446. The problem of fl-SiC formation on surface of silicon substrates annealed in high vacuum. (USSR) Conditions for formation of fl-SiC on the surface of silicon substrates oriented along the (110) plane and annealed in high vacuum are investigated. Electron-graphic analysis showed that E-SiC is formed on the silicon surface during annealing. Formation of SiC occurs in the temperature range of 850 to 1260°C. Annealing at higher temperatures results in clean silicon surfaces. Electron bombardment promotes SiC formation. A strong influence of the residual gas and its composition on SiC growth is observed. The structure of the SiC represents a combination of polycrystals, textured polycrystals and mosaic, the orientation of which is significantly influenced by the orientation of the substrate. Regimes of SiC epitaxial growth were not obtained. O Knznetsov, Proc Rest Krist Plen Polup, Novosibirsk 1970, 226-231
(in Russian). 16 1447. Experimental determination of optimum coverage level for the Ba-W system. (USSR) The optimum coverage of barium on a tungsten ribbon, having the minimum work function, has been determined in an experimental device evacuated to pressure of 1 x 10 9 torr and found to be 3.9x 1014 at/era 2. The optimum Ba atom concentration is 65 per cent of the monolayer concentration. N D Konovalov and E A Tishin, Radiotekh Elektron~ 15 (11), 1970,
2432 (in Russian). 16 : 18 1448. Influence of the vapour of D-1A oil on the emission of oxide cathodes. (USSR) Influence of the vapour of an oil type D-1A on the emission properties of oxide cathodes is investigated. A V Miliyanchuk et al, Fiz Elektron, 3, 1970, 92-93 (in Ukranian). 16 : 18 1449. Influence of helium ion bombardment on the beam current from an oxide cathode. (USSR) Variations of the electron beam current from an oxide cathode due to bombardment of the cathode by helium ions are investigated. R M Kushnir et al, Fiz Elektron, 3, 1970, 89-91 (in Ukranian). 16 1450. Method for evaluation of hydrogen permeation through metalceramic assemblies of electron tubes. (USSR) A method for evaluation of hydrogen permeation through metalceramic assemblies of electro-vacuum devices is described. G V Guskov et al, Elektron Prom, No 1, 1971, 110-112 (in Russian). 16 1451. Kinetics of interaction of caesium vapour with antimony. (USSR) Results of an experimental investigation of the interaction rate of caesium vapour with antimony, in the temperature range 25 to 170°C, are presented, which have been obtained with the aid of precision spring balances. It is shown that the interaction rate is a linear function of the caesium vapour pressure and the rate stays constant in time at the determined caesium vapour pressure. In the investigated temperature range caesium absorption by antimony is 2.5 x 10-5 to 9.5 × 10-2 g/cmZhour for cast antimony and it is increased by factor of 5 for antimony films evaporated in vacuum on nickel substrates. The possibility of preparing getters for caesium vapour pumping in electro-vacuum devices is noted. V P Laguzov, Elektron Tekh Elektron SVCh, 2, 1971, 88-92 (in
Russian). 615
Editor's note The/abe/immediately following the title of each item denotes country or origin o[ publication, and that at the end of each abstract indicates country of origin of work (where known).
I. General v a c u u m science and engineering 14. KINETIC THEORY OF GASES 14 1441. Electric field influence on the thermodiffusion constant of gases. (USSR) Variation of the thermodiffusion constant of the gas mixtures NF3-Ar and C1~O-C180 due to electric field is observed experimentally at pressures from 28 to 58 torr. The experiments are carried out with a pulsing divider. The causes of the effect are considered. V D Borman et al, Zh Eksper Teor Fiz, 60 (5), May 1971, 1627-1629
(in Russian). 16. GASES AND SOLIDS 16 1442. Desorption spectrometry of gases with molecular sieves. I. Theoretical assumptions and measuring equipment. (Germany) Work by other authors on the flash-filament method has suggested the application of their theory to the slow desorption of gases from molecular sieves. This theory and the experimental equipment employed is described. A sample is introduced into a vacuum oven with controlled heating and the desorbed gases are analyzed by mass spectrometer after passage through a suitable system of vacuum and gas inlets. M Durra and K Starke, Vakuum-Technik, 20 (5), July 1971, 129-135
(in German). 16 1443. Gaseous self-diffusion through a porous medium. (USA) The mean free path theory of self-diffusion of "tagged "molecules is formulated for arbitrary Knudsen number in terms of two coupled integral equations. A variational upper bound on the net rate of diffusion through a porous slab is derived. W Strieder, J Chem Phys, 54 (9), 1st May 1971, 4050~053. 16 1444. Structure of carbon monoxide chemisorbed on platinum. (USA) C-O stretching frequencies for 1~C160,13C~60 and 12ClsO chemisorbed on silica supported platinum at 25 ° and 200 ° are used to demonstrate that the bonding to the surface is via the carbon atom. Empirical force constant correlations suggest that the best single structure approximation is Pt = C = O. K C Lin et al, J Chem Phys, 55 (3), 1st August 1971, 1148-1151. 16 1445. Influence of ion bombardment on the physical properties of semiconductors. (USSR) Influence of bombardment by relatively slow ions (energies up to 100 keV) on semiconducting materials is considered. Types of structural defects and investigational methods together with some results are described. The investigation of radiation defects by means of the angular dependence of secondary electron emission is described. Change in the electrical properties of semiconductors due to ion bombardment is studied in detail. Advantages of ion implantation of semiconductors are discussed. Results of investigations on the electrical conductivity of ion implanted layers and its variation during annealing are reviewed. Data on influence of ion bombardment on the behaviour of non-equilibrium charge carriers, radiation conductivity, and luminescence, are presented. Variation of the optical properties of semiconductors due to ion bombardment is also discussed. Influence of ion bombardment on impurity diffusion and the chemical activity of materials is studied. It is concluded that, with the aid of ion bombardment, materials may be produced with properties such as cannot be obtained by other techniques. I A Abroyan, Usp Fiz Nauk, 104 (1), May 1971, 15-50 (in Russian).
16 1446. The problem of fl-SiC formation on surface of silicon substrates annealed in high vacuum. (USSR) Conditions for formation of fl-SiC on the surface of silicon substrates oriented along the (110) plane and annealed in high vacuum are investigated. Electron-graphic analysis showed that E-SiC is formed on the silicon surface during annealing. Formation of SiC occurs in the temperature range of 850 to 1260°C. Annealing at higher temperatures results in clean silicon surfaces. Electron bombardment promotes SiC formation. A strong influence of the residual gas and its composition on SiC growth is observed. The structure of the SiC represents a combination of polycrystals, textured polycrystals and mosaic, the orientation of which is significantly influenced by the orientation of the substrate. Regimes of SiC epitaxial growth were not obtained. O Knznetsov, Proc Rest Krist Plen Polup, Novosibirsk 1970, 226-231
(in Russian). 16 1447. Experimental determination of optimum coverage level for the Ba-W system. (USSR) The optimum coverage of barium on a tungsten ribbon, having the minimum work function, has been determined in an experimental device evacuated to pressure of 1 x 10 9 torr and found to be 3.9x 1014 at/era 2. The optimum Ba atom concentration is 65 per cent of the monolayer concentration. N D Konovalov and E A Tishin, Radiotekh Elektron~ 15 (11), 1970,
2432 (in Russian). 16 : 18 1448. Influence of the vapour of D-1A oil on the emission of oxide cathodes. (USSR) Influence of the vapour of an oil type D-1A on the emission properties of oxide cathodes is investigated. A V Miliyanchuk et al, Fiz Elektron, 3, 1970, 92-93 (in Ukranian). 16 : 18 1449. Influence of helium ion bombardment on the beam current from an oxide cathode. (USSR) Variations of the electron beam current from an oxide cathode due to bombardment of the cathode by helium ions are investigated. R M Kushnir et al, Fiz Elektron, 3, 1970, 89-91 (in Ukranian). 16 1450. Method for evaluation of hydrogen permeation through metalceramic assemblies of electron tubes. (USSR) A method for evaluation of hydrogen permeation through metalceramic assemblies of electro-vacuum devices is described. G V Guskov et al, Elektron Prom, No 1, 1971, 110-112 (in Russian). 16 1451. Kinetics of interaction of caesium vapour with antimony. (USSR) Results of an experimental investigation of the interaction rate of caesium vapour with antimony, in the temperature range 25 to 170°C, are presented, which have been obtained with the aid of precision spring balances. It is shown that the interaction rate is a linear function of the caesium vapour pressure and the rate stays constant in time at the determined caesium vapour pressure. In the investigated temperature range caesium absorption by antimony is 2.5 x 10-5 to 9.5 × 10-2 g/cmZhour for cast antimony and it is increased by factor of 5 for antimony films evaporated in vacuum on nickel substrates. The possibility of preparing getters for caesium vapour pumping in electro-vacuum devices is noted. V P Laguzov, Elektron Tekh Elektron SVCh, 2, 1971, 88-92 (in
Russian). 615