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1.
Using a representation of multichannel quantum defect theory in terms of a quantum Poincaré map for bound Rydberg molecules, we apply Jung's scattering map to derive a generalized quantum map, that includes the continuum. We show that this representation not only simplifies the understanding of the method, but moreover produces considerable numerical advantages. Finally we show under what circumstances the usual semi-classical approximations yield satisfactory results. In particular we see that singularities that cause problems in semi-classics are irrelevant to the quantum map. 相似文献
2.
T. Riesterer J. G. Bednorz K. A. Müller B. Reihl 《Applied Physics A: Materials Science & Processing》1987,44(1):81-82
We have measured ultraviolet and inverse-photoemission spectra of the novel superconductor Sr02La1.8CuO4. Our results compare favorably with recent band-structure calculations for La2CuO4.A full account of this work will be published elsewhere [1] 相似文献
3.
R. Slater 《Applied physics. B, Lasers and optics》1987,42(1):17-20
The rate of build-up of N2 was measured in electron-beam-irradiated Ne/Xe/NF3 mixtures using mass spectroscopy. the amount of N2 produced indicated that N2 is the primary nitrogen bearing stable species created in these mixtures. The rate constant for dissociative electron attachment to the NF2 fragments produced in electron attachment to NF3 is estimated to be 5×10–8 cm3/s in order to explain the amount of N2 produced.This work was supported by DARPA under Contract No. DAA01-82-C-A125 and monitored by MICOM 相似文献
4.
E. M. Azaroual P. Luc R. Vetter 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,24(2):161-164
The use of an effusive beam of titanium atoms crossed with a CW single-mode tunable dye laser has allowed the high-resolution, Doppler-free study of the isotope shifts between50Ti,48Ti and46Ti, for seven 3d
2 4s
2 a3
F
J
3d
2 4s 4p z
5
D
J
, visible transitions of Ti I. The measurements show without ambiguity the existence of a non-negligible field shift. Using the values of the nuclear radii of titanium (coming from muonic X-ray measurements), it is possible to determine the respective values of the field and mass shifts. 相似文献
5.
J. C. Moreno J. Nilsen J. A. Koch B. J. MacGowan J. H. Scofield L. B. Da Silva 《Applied physics. B, Lasers and optics》1994,58(1):3-5
Neon-like niobium X-ray lasers have been studied using both slab and thin-foil target geometries. Niobium foils of various lengths were irradiated from both sides with two beams of the frequency-doubled Nova laser system using a line focus. We looked for gain by measuring spectrally integrated line intensities at different plasma lengths. Gain was observed in four neon-like niobium lines corresponding to 3s–3p transitions. The line profile of theJ = 0–1 line ( = 145.9 ) shows splitting due to the hyperfine effect. Improved contrast in the hyperfine structure is observed as the plasma length is increased. Hyperfine splitting may be relevant to other 3s–3p transitions in neon-like niobium as well as other neon-like X-ray laser systems. 相似文献
6.
Isotonic and isobaric dependencies of nuclear charge radii in the region between Z=54 and Z=70 are obtained from the analysis of isotope shift data r2 and muonic and electron scattering data on r2. They are compared with the predictions of the droplet model and the Hartree-Fock calculations. The isobaric dependencies of r2 have proven to be especially sensitive to the choice of an effective nucleon-nucleon interaction. 相似文献
7.
Yordanka Dimitrova Sigrid D. Peyerimhoff 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,32(3):241-247
The hydrogen-bonded complexes involving formaldehyde and a series of proton donors of varying strengths, have been investigated at different levels of ab initio MO theory. The structures of the studied complexes were SCF optimized at the 6-31G basis set level. The binding energy was estimated employing basis set superposition correction, zero-point vibrations and MP2 correlation contribution at the different basis set: STO-3G; 6-31G; MP2/6-31G; 6-31G**; MP2/6-31G**; 6-311G(2d, 2p) and MP2/6-311G(2d, 2p). Linear relationships were found of the calculated binding energy with: the calculated shift in the carbonyl stretching frequency, the changes in carbonyl bond length and the optimum value of hydrogen-bond distance; furthermore the calculations confirm a parallel trend between the proton-donor ability and the strength of the hydrogen bond. 相似文献
8.
The structural and electronic properties of hydrogen-Cd vacancy complex in CdTe have been studied by using density functional theory. Three typical complexes between hydrogen and Cd vacancy were found in our present study. The stablest complex P2 was predicted by using the formation energy and the binding energy. We found that the formation of the complex is exothermic and its binding energy is extremely large. The analysis of the transition energy level indicates that the forming of the complex turns the double acceptors caused by Cd vacancy to be a single one. The position of the single acceptor deeper than the shallow acceptor derived from the cation vacancy. At the same time, the forming of the complex directly increases the lifetime of the minority carrier from decreasing its concentration. The mechanism of the hydrogen passivation effect was also briefly discussed in our present study. 相似文献
9.
A. Morozov T. Heindl J. Wieser R. Krücken A. Ulrich 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(1):51-57
Continuous and pulsed 12 keV electron beams were used to excite nitrogen
within a gas cell at pressures ranging from 10 to 1400 hPa. The pressure
dependence of the ratio of photon fluxes for emission from vibrational
levels v'=0 and 1 of the C 3Π u state has been studied. The
results confirm the presence of a collisional excitation mechanism
populating v'=0, 1 in addition to electron impact excitation. Rate constants
of (1.27 ±0.04)×10-11 cm3s-1 [ v'=0] and
(2.68 ±0.08)×10-11 cm3s-1 [ v'=1] were measured for
C 3Π u quenching by ground state nitrogen. For electron beam
conditions relative excitation efficiencies of 1:0.59:0.22 for
vibrational levels 0, 1 and 2 were calculated. The recorded flux ratios are
compared with the predictions given by a vibrational relaxation model. 相似文献
10.
B. Castaing 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(3):357-358
Usual turbulence experiments, based on the Taylor hypothesis, differ from true Eulerian measurements. This is the origin of
the apparent discrepancy between a recent two point correlation analysis and the multiplicative cascade picture. Indeed, both
Eulerian and Lagrangian observations perfectly agree with this picture.
Received 19 June 2002 / Received in final form 29 July 2002 Published online 14 October 2002
RID="a"
ID="a"e-mail: bcastain@ens-lyon.fr 相似文献