共查询到20条相似文献,搜索用时 32 毫秒
1.
P. K. Naik V. G. Kagal S. L. Verma S. P. Mhaskar 《Applied Physics A: Materials Science & Processing》1980,23(4):373-380
The thermal desorption spectra of inert gas ions (neon, argon and krypton) injected with various energies (430–1950 eV) into
a polycrystalline molybdenum target with various dosages (6.4×1012−3.9×1014 ions/cm2) are reported. At least four different states of binding of the trapped atoms corresponding to the activation energies for
desorption have been observed from the spectra. The activation energies are found to be relatively insensitive to the species
of the bombarding ion, incident ion energy and the dosage. The shapes of the spectra are strongly influenced by the depth
of penetration of the ions into the solid. The activation energies deduced are in good agreement with those reported for the
migration of atoms and defects in molybdenum. 相似文献
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E. V. Lebedeva A. M. Dyugaev P. D. Grigoriev 《Journal of Experimental and Theoretical Physics》2010,110(4):694-700
A theory of electron bubble transport through the interface between cryogenic liquids is developed based on a new approach
to calculating the potential of interaction of a bubble with the interface. The theory is in good agreement with experiments
on the electric-field dependence of the potential barrier near the interface between liquid 4He, 3He, and vacuum, as well as at the interface between 3He and 4He saturated solutions. It is found that the interaction potential dependence on the distance between the electron bubble
and the interface is isotopically invariant to three versions of such an interface. The dependence of the lifetime of negative
ions in 4He and 3He on the temperature and electric field has been determined using the Kramers theory. 相似文献
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Technical Physics - We report on the results of calculation of the probabilities of rescattering of ultrashort (attosecond) electromagnetic field pulses at one- and two-center negative ions in the... 相似文献
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D. I. Zhukhovitskii W. F. Schmidt E. Illenberger 《Journal of Experimental and Theoretical Physics》2003,97(3):606-614
Stationary states of molecular negative ions (anions) near the surface of a solid are investigated. The lone electron is assumed to interact with a diatomic molecule and the surface of the solid. The energies of electron levels are determined by solving the 2D Schrödinger equation. It is shown that its stable solutions exist at distances from the surface greater than some critical distance, otherwise the electron is detached from the anion. In the case of attraction between the electron and the solid, the interaction potential between the anion and the solid appears to have the Lennard-Jones form and the ion is separated from the surface by some equilibrium distance. 相似文献
6.
The adsorption of Xe on a Ni(100) surface has been studied in UHV between 30 and 100 K using LEED, thermal desorption spectroscopy (TDS), work function (Δφ) measurements, and UV photoemission (UPS). At and below 80 K, Xe adsorbs readily with high initial sticking probability and via precursor state adsorption kinetics to form a partially ordered phase. This phase has a binding energy of ~5.2 kcal/mole as determined by isosteric heat measurements. The heat of adsorption is fairly constant up to medium coverages and then drops continuously as the coverage increases, indicating repulsive mutual interactions. The thermal desorption is first order with a preexponential factor of about 1012 s?1, indicative of completely mobile adsorption. Adsorbed Xe lowers the work function of the Ni surface by 376 mV at monolayer coverage. (This coverage is determined from LEED to be 5.65 × 1014 Xe molecules/cm-2.) For not too high coverages, θ, Δφ(θ) can be described by the Topping model, with the initial dipole moment μ0 = 0.29 D and the polarizability α being 3.5 × 10?24 cm3. In photoemission, the and orbitals show up as intense peaks at 5.56 and 6.83 eV below Ef which do not shift their position as the coverage varies. Multilayer adsorption (i.e. the filling of the second and third layers) can be seen by TDS. The binding energies of these α states can be estimated to range between 4.5 and 3.5 kcal/mole. The results are compared and contrasted with previous findings of Xe adsorption on other transition metal surfaces and are discussed with respect to the nature of the inert-gas-metal adsorptive bond. 相似文献
7.
《Infrared physics》1985,25(1-2):133-139
The different laser radiation interaction mechanisms are briefly discussed together with the theoretical models which explain the thermoelastic regime. A general survey of experimental measurements includes optical techniques and acoustic methods. 相似文献
8.
We study the neutralization of negative hydrogen ions in collisions with multicharged fast ions (including relativistic ions)
by using an approach that allows a simple expression for the neutralization cross section to be derived over a range of collision
parameters where the standard Born approximation breaks down.
Zh. éksp. Teor. Fiz. 115, 1549–1560 (May 1999) 相似文献
9.
此文报道了H+、H+2和H+3离子通过碳膜后,在其中产生的各种微量产物的测量结果.讨论了离子与碳膜作用中的电荷交换过程.分析了这些微量产物的形成机理.实验证明在产物的形成中电荷交换过程起关键作用.研究了离子与碳膜作用中的团簇效应和尾流效应. 相似文献
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G. K. Ustinova 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(7):953-956
Fractionation of particles of solar corpuscular radiation significantly changes from flare to flare; therefore the average regularities derived from the contents of inert gases in lunar samples of different cosmicray exposure age are of particular importance. Simulation of the charge states of inert gas ions (Ne, Ar, Kr, and Xe) in lunar ilmenites suggests possibility of higher solar flare activity and higher hardness of the solar proton spectrum ~1 billion years ago. 相似文献
14.
G. C. Das Surchandra Kh. Ibohanbi Singh 《International Journal of Theoretical Physics》1990,29(4):443-453
Using an appropriate model of the ionosphere, we find the travel time for proton whistlers to go from their source to an observer at a satellite. The results differ from earlier ones. The physical parameters obtained through whistler observations agree with these results. Damping and attenuation of whistlers are related to the ionospheric parameters. 相似文献
15.
M. N. Magomedov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2013,7(4):697-706
The dependences of the specific surface energy (σ) and its isochoric temperature derivative (?σ/?T) V on the degree of compression (V/V 0) of the crystal are calculated on the basis of the Mie-Lennard-Jones pair potential of interatomic interaction. The calculations are performed for all face-centered cubic crystals of inert gases (from Ne to Rn) to the degree of compression V/V 0 = 0.016 along three isotherms: 1K, T m and 300 K, where T m is the melting temperature at zero pressure (V/V 0 = 1). The activation processes such as the creation of vacancies and self-diffusion are taken into account in the calculations. It is shown that the isotherm σ(V/V 0) reaching its maximum at (V/V 0)max sharply decreases upon further compression. The surface energy becomes negative (σ(V/V 0) fr =0) at V/V 0 ≤ (V/V 0) fr < (V/V 0)max which should stimulate the process of crystal fragmentation, i.e., an increase in the specific (per atom) intercrystallite surface. It is shown that at high temperatures the condition of fragmentation holds in the crystal in the case of uniform tension, but it is already in the region of the liquid phase. The values of σ, (?σ/?T) V , the vacancy concentration and the fraction of the diffusion atoms are estimated at the points: V/V 0 = 1, (V/V 0)max and (V/V 0) fr at 1 K, Tm and 300 K. The size evolution of the surface and activation parameters is studied using neon as an example. 相似文献
16.
Das G.C. Karmakar B. Ibohanbi Singh K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(1):86-90
The interaction of the nonlinearity and the dispersiveness causing the solitary waves is studied in a relativistic plasma with negative ions through the derivation of a nonlinear partial-differential equation known as the Korteweg-de Vries equation. The negative ions play a salient part in the existence and behavior of the solitons and could be of interest in laboratory plasmas. First, the observations are made in a nonisothermal plasma, and later the reduction to the nonisothermality of the plasma shows entirely different characteristics as compared to the solitons in the isothermal plasmas. Comparison with the various solitons is emphasized 相似文献
17.
Michishio K Tachibana T Terabe H Igarashi A Wada K Kuga T Yagishita A Hyodo T Nagashima Y 《Physical review letters》2011,106(15):153401
Photodetachment of the positronium negative ion, a bound state of one positron and two electrons, has been observed. Development of a method to produce the ions efficiently using a Na coated tungsten surface has enabled the first observation of the photodetachment. The obtained lower limit of the photodetachment cross section for the wavelength of 1064 nm is consistent with the theoretical calculations reported so far. The experimental field developed in the present work gives new opportunities to explore the quantum mechanical three-body problem and to develop energy-tunable positronium beams. 相似文献
18.
Properties of steady state ion sheath formed in front of a negatively biased metal plate under the influence of negative ions
have been investigated in collisionless argon/SF6 plasma. This experiment is carried out at a fixed discharge voltage and fixed filament heating power. In this experiment,
the decrement in plasma pre-sheath potential drop as well as positive ion drift velocity toward the plate is experimentally
recorded in the presence of negative ions. It is also found that the plasma positive ion density and plasma electron temperature
decrease in the presence of negative ions. These factors attribute to the decrease of ion current toward the plate. Hence
the usual ion sheath expands.
Article presented at the International Conference on the Frontiers of Plasma Physics and Technology, 9–14 December 2002, Bangalore,
India. 相似文献
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