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101.
The time-resolved photoelectron spectra (TRPES) of NaI molecules are calculated by using the time-dependent wave packet method. Two different potential energy curves (adiabatic and diabatic) are adopted in the simulation. The third peak of the photoelectron spectra presented in the adiabatic calculation is induced by the reflection of the wave packet. The oscillating of the wave packet onto the diabatic energy curve is a decreasing process. The comparison of the photoelectron spectra between the two different calculations (adiabatic and diabatic) is presented. 相似文献
102.
M. Said F. Ben Zid C.M. Bertoni Stefano Ossicini 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,23(2):191-199
The electronic properties of rare-earth arsenides have been calculated from first principles. In the calculations we have
treated the rare-earth f electrons both as core-like and as valence-like electrons. We consider the changes in the energy bands and in the density
of states near the Fermi level which are found to be relevant, except for the case of LuAs, and discuss this in relation with
the role played from the rare-earth 5d derived states. Moreover we show that the rare-earth 5d related bands are particularly sensitive to the variation of the lattice constant; change in the lattice constant of less
than 1% leads to a different behaviour with respect to the crossing of the rare-earth 5d derived bands and the As 4p derived bands along the Δ-direction. This point is discussed in connection with the possibility of having a semimetal-semiconductor
transition in the rare-earth arsenides.
Received 22 February 2001 相似文献
103.
C. Bobbert C.P. Schulz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):95-97
Nam(H2O)n Clusters ( n = 1...200, m = 1...50) are formed in a recently build pick-up arrangement. Preformed water clusters traverse a sodium oven, where sodium
atoms are picked up. At low sodium vapour pressure ( < 1×10-4 mbar) pure Na(H2O)n clusters are observed in the mass spectra. At high sodium vapour pressure ( > 1×10-3 mbar) the water cluster pick up more than 50 Na atoms and reaction products Na(NaOH)n ( n = 2, 4...50) dominate the mass spectra. The even number of NaOH units in the products indicate that also in a finite cluster
the reaction occurs in pairs as in the macroscopic reaction.
Received 4 December 2000 相似文献
104.
J. Diebel H. Löwe P. Samorí J.P. Rabe 《Applied Physics A: Materials Science & Processing》2001,73(3):273-279
The IR double-resonance techniques IR/R2PI (infrared/resonant 2-photon ionization), IR/PIRI (infrared-photo-induced Rydberg
ionization) and IR-photodissociation spectroscopy are valuable tools to investigate structure, vibrations, and dynamical processes
of neutral and ionic hydrogen-bonded clusters containing aromatic molecules. In this paper we report on the application of
the IR double-resonance techniques to determine the NH and OH stretching vibrations of 4-aminophenol and 4-aminophenol(H2O)1, both in the neutral (S0) and ionic (D0) ground state. All vibrational frequencies obtained for 4-aminophenol and the cluster are compared with the values obtained
from ab initio and DFT calculations. In the S0 state, a trans-linear arrangement of 4-aminophenol(H2O)1 is obtained containing an O-H·· O hydrogen bond. In the D0 state an overlay of two spectra can be observed resulting from the trans-linear structure and a second structure which contains
a N-H·· O hydrogen bond. The observation of these two structures within the ion is an interesting example of a rearrangement
reaction in the ionic state.
Received: 3 November 2000 / Accepted: 6 November 2000 / Published online: 9 February 2001 相似文献
105.
Muhammad Azeem 《Chinese Journal of Physics (Taipei)》2018,56(5):1925-1930
The fundamental absorption edge of SmN is measured by the optical reflection and the transmission technique using a FTIR spectrometer. The MgF2 passivated thin films of SmN were grown by thermal evaporation. The optical spectra was collated in the energy range of 0.5 to 5.0 eV, and the optical energy gap is measured at 1.2 eV, the same as that of DyN. The measured value of the onset of the absorption in SmN does agree with that theoretically calculated, if the spin–orbit coupling is accounted for. 相似文献
106.
We have investigated electronic and magnetic properties of hexagonal, tetragonal, and orthorhombic GdSi2, using the full-potential linearized augmented plane-wave method based on general gradient approximation for exchange-correlation potential. Antiferromagnetic (AFM) states of the GdSi2 are found from total energy calculations to be energetically more stable, compared to ferromagnetic (FM) states in all of the considered present crystal structures. It is in good agreement with an experimental result. The calculated magnetic moments of valence electrons of the Gd atoms are 0.16, 0.14, and 0.14 μB for hexagonal, tetragonal, and orthorhombic crystal structures in AFM states, respectively, and the Si atoms are coupled antiferromagnetically to the Gd atoms irrespective of crystal structure even though their magnitudes are negligible. 相似文献
107.
Self Mixing Fringes of Vertical-Cavity Surface-Emitting Lasers under Dual Reflector Feedback 下载免费PDF全文
The self-mixing fringes which shift due to every one-twentieth wavelength displacement of the target are observed. Taking advantage of the dual reflectors in the external cavity of lasers, the resolution of the sensors has been improved by 10 times. The role of the each reflector has been discussed in detail. 相似文献
108.
S. Knappe J. Kitching L. Hollberg R. Wynands 《Applied physics. B, Lasers and optics》2002,74(3):217-222
We measure the properties of coherent population trapping (CPT) resonances in Cs vapor cells as a function of temperature.
We expected the CPT signal to increase with higher vapor density, but instead the signal fades away above a certain density.
Two possible density-dependent explanations are discussed: spin-exchange collisions, which are found to give no relevant contribution
at the temperatures considered here, and increased absorption due to the optical thickness of the vapor. The dependence of
the dark-line resonance amplitude as a function of cell temperature can be well represented by a simple model based on the
optical thickness of the vapor as a function of temperature.
Received: 30 November 2001 / Published online: 7 February 2002 相似文献
109.
We introduce a novel concept for optical frequency measurement and division which employs a Kerr-lens, mode-locked laser as
a transfer oscillator whose noise properties do not enter the measurement process. We experimentally demonstrate that this
method opens up the route to phase-link signals with arbitrary frequencies in the optical or microwave range while their frequency
stability is preserved.
Received: 23 July 2001 / Published online: 29 November 2001 相似文献
110.
H. Bielefeldt I. Hörsch G. Krausch M. Lux-Steiner J. Mlynek O. Marti 《Applied Physics A: Materials Science & Processing》1994,59(2):103-108
Opaque samples are imaged by Scanning Nearfield Optical Microscopy (SNOM) in reflection mode: A quartz glass fiber tip is used both to illuminate the sample and to collect light locally reflected from or emitted by the surface. The collected light is coupled out by a 2×2 fiber coupler and fed into a grating spectrometer for spectral analysis at each sampled point. The tip-sample distance is controlled by a shear-force feedback system. The simultaneous measurement of topography and optical signals allows an assessment of imaging artifacts, notably topography-induced intensity changes. It is demonstrated that an optical reflectance contrast not induced by topographic interference can be found on suitable samples. Local spectral analysis is shown in images of a photoluminescent layer. 相似文献