Tunnel spectroscopic measurements in air with a scanning tunnel microscope

Central methodical and hardware problems in taking spectra of different types with a scanning tunneling microscope in air are briefly discussed. Ways to overcome these problems are considered. A procedure for recording a new type of tunneling spectra, namely, voltage-height (U-H) curves, which allow the estimation of the probe-specimen gap, is offered. It is suggested that the current flowing in the course of measurements in air is of electrochemical nature. Different tunnel spectra for metal, oxide, carbon, and polymer materials, including heterogeneous substances, are presented to illustrate the experiments.     

Laser photoionization spectroscopy of rare-earth elements: New results on nuclear electromagnetic moments and charge radii of Eu,Gd and Tb isotopes

New results on spins, electromagnetic moments and isotopic changes of nuclear charge radii for ₆₃ ^157–159 Eu, ₆₄ ^{146, 148, 150} Cd and ₆₅ ^{147–155, 157, 159} Tb have been obtained from hyperfine structure and isotope shifte measured with laser resonance photoionization technique. These results complement two-dimensional picture (with respect to H and Z) of the changes of nuclear ground state properties near the “critical” neutron numbers N=88–90 in the vicinity of the “magric” proten number Z=64.     

Effect of photoexcited carriers on Raman spectra of a hydrogenated GaAs crystal implanted with silicon

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 53, No. 1, pp. 116–121, July, 1990.     

Solution of some inverse problems in nonequilibrium sorption dynamics

The paper considers inverse problems of sorption dynamics that determine the sorption isotherm from the output curve. Uniqueness theorems are proved for these inverse problems. Numerical solution methods are constructed. Some applications to model problems are described.Translated from Metody Matematicheskogo Modelirovaniya, Avtomatizatsiya Obrabotki Nablyudenii i Ikh Primeneniya, pp. 5–15, 1986.     

Extended Cylindrical Low-Pressure Arc Discharge Plasma Emitter for Generation of a Radially Diverging Electron Beam

Russian Physics Journal - The paper presents the results of studies of processes of generation of a beam-plasma formation in an extended cylindrical hollow mesh anode with a diameter of 115 mm and...     

Synthesis,Crystal Structure,and Thermal Properties of Substituted Titanates Bi2Pr2Ti3O12 and Bi2Nd2Ti3O12

Physics of the Solid State - Titanates Bi2Pr2Ti3O12 and Bi2Nd2Ti3O12 have been obtained by the solid-phase synthesis using sequential annealing of the Bi2O3, Nd2O3, Pr6O11, and TiO2 stoichiometric...     

Optical Properties of Three-Dimensional InGaP(As) Islands Formed by Substitution of Fifth-Group Elements

Optics and Spectroscopy - The optical properties of three-dimensional quantum-size InGaPAs islands, which are formed by substitution of phosphorous by arsenic in an InGaPAs layer deposited on GaAs...     

A Method for Detecting and Localizing Inhomogeneities in Plates Using Lamb Waves

Acoustical Physics - The paper presents the results from a study of the interaction of Lamb waves with inhomogeneities in composite plates. It was found that waves of this type are diffracted by...     

Synthesis,Crystal Structure,Luminescence, and Thermophysical Properties of TbGaGe2O7

Physics of the Solid State - Germanate TbGaGe2O7 has been obtained from the initial Tb2O3, Ga2O3, and GeO2 oxides by the solid-phase synthesis. The germanate structure has been established by X-ray...     

Molecular decomposition of polyolefins: Kinetic parameters and geometry of the transition state

The experimental data on the molecular decomposition of olefins ( 1 -pentens) of various structures to two olefins in a gas phase were analyzed by means of the parabola intersection method. The enthalpies and kinetic parameters characterizing such decomposition were calculated for eighteen reactions. Decomposition of olefins representing two-centered concerted re action was found to be characterized by a very high classic potential barrier of thermoneutral reaction (197.4 kJ/mol). The kinetic parameters (activation energy and velocity constant) of fifteen reverse reactions of formation of olefins from two alkenes were calculated using the parabola-intersection method. The factors affect ing the activation energy of the reactions of olefin decomposition and formation are discussed. Quantum chemical calculations of the transition state energy and geometry for six reactions of olefin decomposition were performed.