73 research outputs found
Nuclear resonant scattering of synchrotron radiation by physisorbed Kr on TiO(110) surfaces in multilayer and monolayer regimes
Physisorbed Kr layers on TiO(110) surfaces were investigated by means
of nuclear resonant scattering (NRS) of synchrotron radiation at Kr thicknesses
ranging from multilayer to monolayer. The NRS intensity was measured as a
function of the Kr exposure, from which the NRS signal corresponding to
monolayer was estimated as 0.23 cps. The time spectra measured at various
thicknesses showed a monotonous decay without any quantum beat features. The
recoiless fraction evaluated from the analysis of the time spectrum
revealed a substantial reduction upon temperature rise from 19 to 25 K. As its
origin, an order-disorder phase transition of the monolayer Kr is proposed.Comment: 7 pages, 6 figure
Resonant tunneling of Hydrogen in Pd
Please click Additional Files below to see the full abstrac
Nuclear resonant scattering of synchrotron radiation by physisorbed Kr on TiO2(110) surfaces in multilayer and monolayer regimes
Physisorbed Kr layers on TiO2(110) surfaces were investigated by means of nuclear resonant scattering (NRS) of synchrotron radiation at Kr thicknesses ranging from multilayer to monolayer. The NRS intensity was measured as a function of the Kr exposure, from which the NRS signal corresponding to monolayer was estimated as 0.23 cps. The time spectra measured at various thicknesses showed a monotonous decay without any quantum beat features. The recoilless fraction f evaluated from the analysis of the time spectrum revealed a substantial reduction upon temperature rise from 19 to 25 K. As its origin, an order-disorder phase transition of the monolayer Kr is proposed
Classification of Light-Induced Desorption of Alkali Atoms in Glass Cells Used in Atomic Physics Experiments
We attempt to provide physical interpretations of light-induced desorption
phenomena that have recently been observed for alkali atoms on glass surfaces
of alkali vapor cells used in atomic physics experiments. We find that the
observed desorption phenomena are closely related to recent studies in surface
science, and can probably be understood in the context of these results. If
classified in terms of the photon-energy dependence, the coverage and the
bonding state of the alkali adsorbates, the phenomena fall into two categories:
It appears very likely that the neutralization of isolated ionic adsorbates by
photo-excited electron transfer from the substrate is the origin of the
desorption induced by ultraviolet light in ultrahigh vacuum cells. The
desorption observed in low temperature cells, on the other hand, which is
resonantly dependent on photon energy in the visible light range, is quite
similar to light-induced desorption stimulated by localized electronic
excitation on metallic aggregates. More detailed studies of light-induced
desorption events from surfaces well characterized with respect to alkali
coverage-dependent ionicity and aggregate morphology appear highly desirable
for the development of more efficient alkali atom sources suitable to improve a
variety of atomic physics experiments.Comment: 6 pages, 1 figure; minor corrections made, published in e-Journal of
Surface Science and Nanotechnology at
http://www.jstage.jst.go.jp/article/ejssnt/4/0/4_63/_articl
On the reflection symmetries of atoms and diatomic molecules: derivation of
The reflection symmetries of atoms and diatomic molecules are discussed in detail. We introduce the classification of the atomic states in light of their transformational properties for reflection, and show the absence of the negative terms, namely S− terms, in the one- and two-electron systems. The selection rule that no dipole transition occurs between S terms is readily derived using only the reflection symmetry. We also give an elementary proof of the rule on determining molecular Σ± terms from atomic terms. Furthermore, based on the picture of the electron configuration in molecular orbitals, general functional forms of Σ± states are shown. By using these forms, we derive the resultant Σ± terms for the electron configurations that have not been treated previously, and make clear what causes the correlation between the reflection symmetry and spin multiplicity. The way shown in the present paper enables determination of Σ± terms arising from any electron configuration
- …