Ion mixing in multilayer films and the doping of the near-surface layers of polycrystalline substrates under irradiation by ion beams with a wide energy spectrum

Various factors influencing ion mixing efficiency are considered. It is established that the energy transfer from ions and primary knocked-on atom films to subsequent displacement cascades underlies the penetration of atoms from multilayer films into a polycrystalline substrate. The penetration of implanted atoms to great depths is in this case determined by the defect density, the radiation induced migration of the implanted atoms, and their interaction with the atoms of the matrix. All of these factors can be described in terms of the isotropic mixing model. It is shown that when doped by atoms from multilayer films, gradient layers form that are determined by the range of radiation in the substrate of the atoms to be implanted and their migration under irradiation by an ion beam with a wide range of energies.     

Influence of a metal surface on the luminescence of adsorbed europium compounds

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 130–134, November–December, 1995.     

Doping of ZrO2 by ion mixing

The morphology and structure of ZrO₂ films grown in steam-water medium on an ion-doped surface of zirconium and its E110 and E635 alloys have been studied. It has been found that the properties of oxide films are determined mostly by the conditions of ion-implantation doping at large oxidation times. It has been shown by the example of samples doped simultaneously with Al, Fe, Mo, and Y that the formation of a multiphase oxide film occurs due to the diffusion redistribution of implanted atoms during oxidation.     

Reactivity of the Indenyl Radical (C9H7) with Acetylene (C2H2) and Vinylacetylene (C4H4)

The reactions of the indenyl radicals with acetylene (C₂H₂) and vinylacetylene (C₄H₄) is studied in a hot chemical reactor coupled to synchrotron based vacuum ultraviolet ionization mass spectrometry. These experimental results are combined with theory to reveal that the resonantly stabilized and thermodynamically most stable 1-indenyl radical (C₉H₇^.) is always formed in the pyrolysis of 1-, 2-, 6-, and 7-bromoindenes at 1500 K. The 1-indenyl radical reacts with acetylene yielding 1-ethynylindene plus atomic hydrogen, rather than adding a second acetylene molecule and leading to ring closure and formation of fluorene as observed in other reaction mechanisms such as the hydrogen abstraction acetylene addition or hydrogen abstraction vinylacetylene addition pathways. While this reaction mechanism is analogous to the bimolecular reaction between the phenyl radical (C₆H₅^.) and acetylene forming phenylacetylene (C₆H₅CCH), the 1-indenyl+acetylene→1-ethynylindene+hydrogen reaction is highly endoergic (114 kJ mol⁻¹) and slow, contrary to the exoergic (−38 kJ mol⁻¹) and faster phenyl+acetylene→phenylacetylene+hydrogen reaction. In a similar manner, no ring closure leading to fluorene formation was observed in the reaction of 1-indenyl radical with vinylacetylene. These experimental results are explained through rate constant calculations based on theoretically derived potential energy surfaces.     

Influence of heteroligand complexation on the thermal, photoluminescent, and film-forming properties of some aromatic terbium(III) carboxylates

With homoligand TbL₃ and heteroligand complexes TbL₃(Q)_n (HL = HSal (salicylic acid) and HPA (2-anilinobenzoic acid); Q = TPPO (triphenylphosphine oxide) and TOPO (tri(n-octyl)phosphine oxide); n = 1 or 2) as examples, it was shown that heteroligand complexation affects not only the thermal and photoluminescent properties but also the quality of films obtained by centrifugation: the root-mean-square roughness changes in the order TbL₃Q > TbL₃(Q)₂ ≈ TbL₃. This is due to different association degrees of the complexes in solution, which was confirmed by MALDI-TOF MS data.     

Stress-strain state of a half-space in the neighborhood of a stiff sphere subjected to a normal load

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Ultrahard Materials, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 24, No. 4, pp. 19–25, April, 1988.     

Crown-ether styryl dyes

The surface enhanced Raman scattering (SERS) spectra of styryl dyes containing a crown-ether group and a heteroaromatic residue with sulfoalkyl (1a) or alkyl (1b)N-substituent and of their complexes with Mg²⁺ cations were recorded in the 10^–4–10^–8 mol L^–1 concentration range. A model for the interaction of compoundsla,b with a silver surface during their adsorption on an electrochemically treated electrode was suggested. Fastcis-trans relaxation of the adsorbed molecules1a,b and complexes (1a,b)Mg²⁺ was found. It was shown that at [1a] = 10^–5 mol L^–1 and moderate molar ratios (C _Mg/[1a] = 3/1 to 9/1) in acetonitrile solutions, (trans-1a)Mg²⁺ complexes are joined into head-to-tail type dimers. An excess of Mg²⁺ cations (C_Mg/[1a] > 100) leads to dissociation of the dimers yielding (trans-1a)(Mg²⁺)₂ complexes. The formation of dimers from complexes (trans-1a)Mg²⁺ is accompanied by a substantial distortion of the planar structure oftrans-1a. This may be an important factor influencing the efficiency of photocycloaddition involving dimers of (trans-1a)Mg²⁺.For part 15, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2429–2436, December, 1995.The work was carried out with financial support of the Russian Foundation for Basic Research (Project No. 94-03-08760) and, to some extent, of INTAS (Grant No. 93-1829) and of the International Science Foundation (Grant No. MHAOOO).     

Measuring the electrical conductivity and the hall coefficient for semiconductor structures inhomogeneous with depth

The well-known four-point probe method of combined measurements of electrical conductivity and the Hall coefficient of semiconductor layers is developed further in the present work. Formulas are derived that allow the electrical conductivity and the Hall coefficient to be averaged over layers inhomogeneous with depth. Analytical expressions for calculating correction factors for this measurement method are obtained, and practical recommendations for their calculation on a computer are also given. Lipetsk State Pedagogical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 46–51, January, 2000.