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868. Diffusion coefficient and heat of transport of H and D in niobium below room temperature
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866-875
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866-991
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The label immediately following the title of each item denotes country or origin of publication, that at the end of each abstract indicates country of origin of work (where known).
I.
General
16. GASES
vacuum
AND
science
and engineering
SOLIDS
16 866. Generation of electron-hole pairs in In,Se single crystals on bombardment by electrons with 100 to 5000 eV energy. (USSR) Variations in conductivity of In,Se single crystals on bombardment by electrons with 100 to 5000 eV energy are investigated. It is found that the mechanism of electron interaction with crystal changes on enhancement of the electron energy. The results of experiments are explained on the basis of assumption of possibility of dissociation of In,Se with short-time transition of In in the donor state. A V Miliyanchuk et al, Phys Electron, Rep Intrrdiscipl Scient-tech Coil, No 7. 1974, 49-52 (in Russian). I6 867. Raman study of the vibrational properties of implanted silicon. (Germany) Lattice disorder created during ion bombardment, thickness of perturbed layer and subsequent annealing behaviour have been studied in room temperature implanted silicon at 70 to 80 keV using Raman spectroscopy. It is found that saturation of the disorder occurs for energy of 3 x 10Z4 eV crnm3 deposited into atomic (nuclear) processes. The thickness of the perturbed layer at this energy varies between 500 and 100 8, depending upon the projectile mass. The annealing of implantation damage in silicon bombarded with P, Ar, As occurs at approximately 600°C and varies only slightly with implanted impurity. J F Morhange et al, Phys Stat sol (a), 23 (2), 1974, 383-39 I. 16 868. Diffusion coefficient and heat of transport of H and D in niobium below room temperature. (Germany) The diffusion coefficient and the heat of transport of H and D in niobium were determined by resistance measurements for concentrations between 0.01 and 0.15 atomic per cent. Measurements were performed on samples which were made from 12.5 to 50 pm thick foils. In order to reduce the carbon content the foils were heated about 30 min in an oxygen atmosphere of IO-’ torr at 19OO”C, hereupon they were degassed for I h at 2300°C at lo-” torr. The loading of the samples-with H or D was done electrolytically. An activation energy of 0.123 i 0.006 eV was measured for D in the whole temperature range investigated (150 to 320 K). For H a pronounced break in the Arrhenius plot was found at about 225 K in agreement with Gorsky effect measurements. H Wipf and G Alefeld, Phys Stat Sol (a), 23 (l), 1974, 175-186. 16 869. Silicon adsorption on single-crystal faces of tungsten. (Germany) Silicon adsorption on single-crystal faces of tungsten was studied in a field emission microscope. The variation in work function with surface adatom density has been determined for several planes and these results were utilized in calculating dipole moments and effective adsorbate polarizabilities. An attempt to fit the results to a simple point-dipole depolarization model was only partially successful. (England) C A Kiwanga and R A Collins, Phys Stat Sol (a), 23 (I), 1974, 209-2 14. 16 870. Comparison of spectra of characteristic losses of energy of lowenergy electrons with optical absorption spectra in anthracene and copper phtalocyanine. (USSR) The mechanism of interaction of 100 eV electrons with crystals is discussed on the basis of comparison of experimental spectra of characteristic losses of energy of low-energy electrons with optical absorption spectra in anthracene and copper phtalocyanine. L Ya Bubnov and E L Frankevich, Fiz Trerd Telu, 16 (5), 1974, I5331534 (in Russian). 284
and
I (3
871. The influence of discrete structure of lattice of atoms on scattering of ions by crystals. (USSR) The dependence of intensity of scattered 30 keV ions from the ( I IO) copper face on the incidence angle of primary ions is investigated. The influence of discrete structure of lattice of atoms on scattering of ions by crystals is discussed. Yu G Skripka and A P Trynkin, FiFi’-Twrd Telu. 15 (51, 1974. Ii45 I546 (in Russian).
Ih 872. Interaction of low-energy electrons with atomically clean (I IO), (100) Si and (111) Ge faces. (USSR) The dependence of intensities of reflected beams at low-energq electron diffraction on the energy of incident beam and target temperature is investigated on atomically clean (I lo), (100) Si and (I I I ) Ge faces. The surfaces of investigated samples were cleaned by argon ion bombardment and heating in ultrahigh vacuum. The measurcments have been made at a pressure of 3 1 IO-‘” torr. The values of inner potential are 9 eV for Si and 17 eV for Ge as determined from investigation of intensities of reflected beams. It is found that the half-width of Bragg maxima does not depend on temperature. The depth of penetration of electrons into the lattice is estimated to be 3 to 15 8, and it does not depend on energy. It is concluded that the electron-electron interaction plays the dominant role in the processes of inelastic scattering of low-energy electrons. It is found that the distance between atomic layers, averaged in the thickness of reflection, agrees with the bulk value within IT/,. B A Nesterenko et al, Fiz Tuerd Telu, 16 (5), 1974, 1278-I 284 (i/r Russian). I6 873. Mass spectrometry of surface of epitaxially grown GaP single crystals. (Czechoslovakia) Secondary mass spectra of surface of epitaxially grown GaP single crystals are presented. Argon ion primary beam and quadrupole mass analyzer were used in experiments. P Kacerovsky, Elektrotech Gas, 25 (4-6), 1974, 386-389 (in C:wh).
18. GASEOUS
ELECTRONICS
IX 874. Factors influencing the relative frequency stability of He&Xe laser structures. (USA) 6328 w He-Ne laser structures, made from ultralow expansion matcrials, suspended in temperatureand pressure-controlled chambers, have shown drift rates in excess of t 5 MHz/day. The same structure evacuated and used as passive Fabry-Perot resonators, suspended in the previous now evacuated chambers, still show a drift rate of the order of 12 MHz/day. Computer simulated mirror model aging shows that relatively large changes of the dielectric constants of the mirror coatings are needed to explain the measured drift. We feel that the dimensional stability of the materials and the properties of the optical contacts used, as well as the behaviour of the dielectric mirrors, have to be more carefully investigated. U E Hochuli et al, Rev Scient Instrum, 45 (I I), 1974. I378- I38 I,
1x 875. Excitation mechanisms in the nresence of moving striations in an He/Cd cataphoretic laser discharge: (GB) The analysis of spontaneous sidelight from an He/Cd cataphoretic laser has-revealedthat the discharge, at optimum lasing conditions, contains two dominant excitation processes leading to inversion of the 441.6 nm transition, namely Penning ionization and direct electron excitation. The results show that previous analyses of the glow discharge, based on the assumption of a maxwellian electron
abstracts
Editor’s
866-875
abstracts
866-991
on this page
note
The label immediately following the title of each item denotes country or origin of publication, that at the end of each abstract indicates country of origin of work (where known).
I.
General
16. GASES
vacuum
AND
science
and engineering
SOLIDS
16 866. Generation of electron-hole pairs in In,Se single crystals on bombardment by electrons with 100 to 5000 eV energy. (USSR) Variations in conductivity of In,Se single crystals on bombardment by electrons with 100 to 5000 eV energy are investigated. It is found that the mechanism of electron interaction with crystal changes on enhancement of the electron energy. The results of experiments are explained on the basis of assumption of possibility of dissociation of In,Se with short-time transition of In in the donor state. A V Miliyanchuk et al, Phys Electron, Rep Intrrdiscipl Scient-tech Coil, No 7. 1974, 49-52 (in Russian). I6 867. Raman study of the vibrational properties of implanted silicon. (Germany) Lattice disorder created during ion bombardment, thickness of perturbed layer and subsequent annealing behaviour have been studied in room temperature implanted silicon at 70 to 80 keV using Raman spectroscopy. It is found that saturation of the disorder occurs for energy of 3 x 10Z4 eV crnm3 deposited into atomic (nuclear) processes. The thickness of the perturbed layer at this energy varies between 500 and 100 8, depending upon the projectile mass. The annealing of implantation damage in silicon bombarded with P, Ar, As occurs at approximately 600°C and varies only slightly with implanted impurity. J F Morhange et al, Phys Stat sol (a), 23 (2), 1974, 383-39 I. 16 868. Diffusion coefficient and heat of transport of H and D in niobium below room temperature. (Germany) The diffusion coefficient and the heat of transport of H and D in niobium were determined by resistance measurements for concentrations between 0.01 and 0.15 atomic per cent. Measurements were performed on samples which were made from 12.5 to 50 pm thick foils. In order to reduce the carbon content the foils were heated about 30 min in an oxygen atmosphere of IO-’ torr at 19OO”C, hereupon they were degassed for I h at 2300°C at lo-” torr. The loading of the samples-with H or D was done electrolytically. An activation energy of 0.123 i 0.006 eV was measured for D in the whole temperature range investigated (150 to 320 K). For H a pronounced break in the Arrhenius plot was found at about 225 K in agreement with Gorsky effect measurements. H Wipf and G Alefeld, Phys Stat Sol (a), 23 (l), 1974, 175-186. 16 869. Silicon adsorption on single-crystal faces of tungsten. (Germany) Silicon adsorption on single-crystal faces of tungsten was studied in a field emission microscope. The variation in work function with surface adatom density has been determined for several planes and these results were utilized in calculating dipole moments and effective adsorbate polarizabilities. An attempt to fit the results to a simple point-dipole depolarization model was only partially successful. (England) C A Kiwanga and R A Collins, Phys Stat Sol (a), 23 (I), 1974, 209-2 14. 16 870. Comparison of spectra of characteristic losses of energy of lowenergy electrons with optical absorption spectra in anthracene and copper phtalocyanine. (USSR) The mechanism of interaction of 100 eV electrons with crystals is discussed on the basis of comparison of experimental spectra of characteristic losses of energy of low-energy electrons with optical absorption spectra in anthracene and copper phtalocyanine. L Ya Bubnov and E L Frankevich, Fiz Trerd Telu, 16 (5), 1974, I5331534 (in Russian). 284
and
I (3
871. The influence of discrete structure of lattice of atoms on scattering of ions by crystals. (USSR) The dependence of intensity of scattered 30 keV ions from the ( I IO) copper face on the incidence angle of primary ions is investigated. The influence of discrete structure of lattice of atoms on scattering of ions by crystals is discussed. Yu G Skripka and A P Trynkin, FiFi’-Twrd Telu. 15 (51, 1974. Ii45 I546 (in Russian).
Ih 872. Interaction of low-energy electrons with atomically clean (I IO), (100) Si and (111) Ge faces. (USSR) The dependence of intensities of reflected beams at low-energq electron diffraction on the energy of incident beam and target temperature is investigated on atomically clean (I lo), (100) Si and (I I I ) Ge faces. The surfaces of investigated samples were cleaned by argon ion bombardment and heating in ultrahigh vacuum. The measurcments have been made at a pressure of 3 1 IO-‘” torr. The values of inner potential are 9 eV for Si and 17 eV for Ge as determined from investigation of intensities of reflected beams. It is found that the half-width of Bragg maxima does not depend on temperature. The depth of penetration of electrons into the lattice is estimated to be 3 to 15 8, and it does not depend on energy. It is concluded that the electron-electron interaction plays the dominant role in the processes of inelastic scattering of low-energy electrons. It is found that the distance between atomic layers, averaged in the thickness of reflection, agrees with the bulk value within IT/,. B A Nesterenko et al, Fiz Tuerd Telu, 16 (5), 1974, 1278-I 284 (i/r Russian). I6 873. Mass spectrometry of surface of epitaxially grown GaP single crystals. (Czechoslovakia) Secondary mass spectra of surface of epitaxially grown GaP single crystals are presented. Argon ion primary beam and quadrupole mass analyzer were used in experiments. P Kacerovsky, Elektrotech Gas, 25 (4-6), 1974, 386-389 (in C:wh).
18. GASEOUS
ELECTRONICS
IX 874. Factors influencing the relative frequency stability of He&Xe laser structures. (USA) 6328 w He-Ne laser structures, made from ultralow expansion matcrials, suspended in temperatureand pressure-controlled chambers, have shown drift rates in excess of t 5 MHz/day. The same structure evacuated and used as passive Fabry-Perot resonators, suspended in the previous now evacuated chambers, still show a drift rate of the order of 12 MHz/day. Computer simulated mirror model aging shows that relatively large changes of the dielectric constants of the mirror coatings are needed to explain the measured drift. We feel that the dimensional stability of the materials and the properties of the optical contacts used, as well as the behaviour of the dielectric mirrors, have to be more carefully investigated. U E Hochuli et al, Rev Scient Instrum, 45 (I I), 1974. I378- I38 I,
1x 875. Excitation mechanisms in the nresence of moving striations in an He/Cd cataphoretic laser discharge: (GB) The analysis of spontaneous sidelight from an He/Cd cataphoretic laser has-revealedthat the discharge, at optimum lasing conditions, contains two dominant excitation processes leading to inversion of the 441.6 nm transition, namely Penning ionization and direct electron excitation. The results show that previous analyses of the glow discharge, based on the assumption of a maxwellian electron