共查询到20条相似文献,搜索用时 0 毫秒
1.
Brillouin scattering is used as a sensitive probe of structural properties of gases adsorbed on porous glass. Evidence is seen for extensive supercooling behavior in both oxygen and nitrogen. 相似文献
2.
The experimental line shape broadening observed in adsorbate diffusion on metal surfaces with increasing coverage is usually related to the nature of the adsorbate-adsorbate interaction. Here we show that this broadening can also be understood in terms of a fully stochastic model just considering two noise sources: (i) a Gaussian white noise accounting for the surface friction, and (ii) a shot noise replacing the physical adsorbate-adsorbate interaction potential. Furthermore, contrary to what could be expected, for relatively weak adsorbate-substrate interactions the opposite effect is predicted: line shapes get narrower with increasing coverage. 相似文献
3.
von Bergmann K Bode M Kubetzka A Heide M Blügel S Wiesendanger R 《Physical review letters》2004,92(4):046801
Scanning tunneling spectroscopy (STS) on the system of isolated oxygen atoms adsorbed on the double layer of Fe on W(110) shows highly anisotropic spatial oscillations in the local density of states in the vicinity of the adsorbates. We explain this in terms of a single-particle model as electron waves being scattered by the potential induced by the presence of the oxygen atoms. Analysis of the wavelength of the standing electron waves and comparison with ab initio spin-resolved electronic structure calculations reveal that minority-spin bands of d-like symmetry are involved in the scattering process. By applying spin-polarized STS, we observe this standing wave pattern on one particular type of magnetic domain of Fe on W(110) only, thereby proving that the standing electron waves are highly spin polarized. 相似文献
4.
A. D. Sinelnik K. B. Samusev S. Yu. Lukashenko Yu. S. Kivshar M. F. Limonov M. V. Rybin 《JETP Letters》2017,105(6):352-356
“Photonic graphene” structures—submicron two-dimensional dielectric structures with a honeycomb lattice— are fabricated by laser lithography. The transition from the regime of light scattering by a metasurface to that of Laue diffraction at a two-dimensional photonic structure in the optical range is studied experimentally and theoretically. The optical diffraction patterns make it possible to determine the number of unit cells in a finite microstructured sample with the naked eye. 相似文献
5.
A recently published model of surface enhanced Raman scattering from adsorbed molecules on semiconductor surfaces is compared to our experimental results for amorphous carbon on PbTe. The model fails to account for the major features of the observed scattering. 相似文献
6.
A. K. Sood 《Hyperfine Interactions》1987,37(1-4):365-384
This paper presents a review of light scattering results on static and dynamic properties of ordered colloidal suspensions
of charged polystyrene particles and fractal colloidal aggregates. Our studies on static structure factor,S(Q), of ordered monodisperse colloidal suspensions and binary mixtures of particles with different particle diameters, measured
by angle-resolved Rayleigh scattering will be discussed. This will include determination of bulk modulus using gravitational
compression and observation of colloidal glass (inferred from splitting of the second peak inS(Q)). Dynamic light scattering, with real time analysis of scattered intensity fluctuations, is used to get information about
Brownian dynamics of the particles. Recent advances in the field of light scattering from colloidal aggregates which show
fractal geometry will also be discussed. 相似文献
7.
We propose an extension of the charge transfer model of surface enhanced Raman scattering (SERS) at silver surfaces. Within an incoherent approximation we include propagating hot electrons, created or annihilated by increased photon-electron coupling at disordered (internal) surfaces. The hot electrons are inelastically scattered by the adsorbates. In “shape resonances” of the free molecule the corresponding cross section is 14 orders of magnitude larger than the ordinary Raman cross section. We list results related to photon-electron coupling and inelastic scattering of electrons by molecules and discuss open problems. 相似文献
8.
9.
《Physics letters. [Part B]》1987,184(1):83-88
We show that for small quark masses, low temperatures and large volumes, the main features of the QCD partition function can be predicted on the basis of chiral symmetry. In particular, we establish a low-temperature theorem which governs the temperature dependence of the fermion condensate. 相似文献
10.
E. Krotscheck R. E. Zillich 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):113-116
We present a microscopic theory and results of atom
scattering calculations to determine the dispersion of surface modes
(ripplons) of superfluid helium-4 nanodroplets, expanding previous
work [J. Chem. Phys. 115, 10161 (2001)]. A quantum transport formalism is
adapted to the many-body scattering problem, yielding both elastic and
inelastic fluxes. We demonstrate that, in analogy to the dynamic
structure function S(k,ω) obtained from neutron scattering, a
dynamic structure function σ(k,ω) can be obtained from
3He scattering. The 3He dynamic structure function
σ(k,ω) is sensitive to surface dynamics,
whereas the neutron dynamic structure function S(k,ω) is
dominated by bulk-like excitations, in particular by rotons.
Unlike for neutron-scattering, the total inelastic cross section for
atom-scattering on 4He nanodroplets is large which we believe makes
experimental detection feasible. We also show that scattering identical particles, i.e. 4He atoms, does not provide
information about the dispersion of surface modes. Instead,
inelastically scattered 4He atoms preferably lose roughly half
their energy. 相似文献
11.
L. Vriens 《Physics letters. A》1976,55(6):331-332
Cross sections are calculated for near-resonant light scattering from n=2 excited hydrogen atoms. Previous derivations of these cross sections are shown to be incorrect. 相似文献
12.
Efficient collection of the scattered light from adsorbates on silver in the attenuated total reflection configuration is demonstrated with a so-called Weierstrass prism. The Raman signal from carbon contamination on silver films is enhanced by two orders of magnitude with respect to the simple external backscattering configuration. 相似文献
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16.
In this paper two different physical situations are considered which can be treated with the same method: a fluid adsorbate (disordered in the x, y plane) and a clean surface with random steps (disordered in the z direction). The hard corrugated wall model is used in the eikonal approximation; the differences between the two cases arise only from the different statistical properties of the two physical situations. The differential scattering probability is evaluated. For the fluid adsorbate the latter splits into a coherent (purely specular) contribution and an incoherent one (which is, in fact, weakly inelastic and related to classical diffusion on the surface). For stepped “rough” surfaces only incoherent scattering is present and the differential scattering probability for hexagonal lattices is given. 相似文献
17.
The NaCl(001) surface is studied using an H atom beam at energies of 76.3 and 86.3 meV. Elastic diffractive scattering is investigated under different incident angles and crystal orientations. Selective adsorption resonances are measured, determining experimentally the energy levels of the H atom bound to the surface. The energy spectrum is reproduced reasonably by a Morse potential with a well depth D = 29.2 meV and a range parameter k = 0.04 nm?1. 相似文献
18.
A. Ghoshal Y. K. Ho 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(3):581-589
Elastic scattering of positrons from the hydrogen atoms in weakly-coupled plasmas has
been studied using an expression for partial wave scattering amplitude that
has been derived within the framework second order distorted wave Born approximation.
The interactions among the charged particles in the plasma have been represented by Debye-Hückel potentials. A detailed study
has been made on differential and total cross sections in the energy range 20–300 eV. To the best of our knowledge such a
study on the differential and total cross sections for elastic positron-hydrogen collisions in a weakly-coupled plasma environment
is reported for the first time in the literature. 相似文献
19.
Snoke DW 《Physical review. B, Condensed matter》1993,47(20):13346-13352
20.
Light scattering measurements along the coexistence line show that reorientation in liquid HCl, DCl, and HBr is strongly hindered at low temperature and collision limited on approaching the critical point. Discrepancies with NMR data are observed. 相似文献