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1.
-1 to 50000 cm-1, exhibiting an extinction maximum that could be assigned to the corresponding long-axis surface plasmon excitation in the
spheroidal noble metal particles. For simulation of the measured spectra, the model of Gans [Ann. Phys. 37, 881 (1912)] was used to calculate the optical extinction spectrum for each analyzed particle in a sample. The various spectra
of more than 500 particles were added up to get the total extinction spectrum of the sample, yielding very good agreement
with the measured spectra. A remaining blueshift of the computed spectra compared to the measured spectra could be explained
by considering electromagnetic interaction among the particles.
Received: 22 July 1998 / Revised version: 22 October 1998 / Published online: 24 February 1999 相似文献
2.
N. Petit V. Garnier V. Ta Phuoc R. Caillard A.-M. Frelin A. Ruyter I. Laffez J.-C. Soret A. Maignan F. Gervais 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,25(4):423-429
The reflectivity spectra of an oriented ceramic of Bi-2223 has been investigated by polarized infrared reflectivity spectroscopy
in the energy range 0.005-2.2 eV. It is shown that the data for the polarization parallel to the c axis cannot be fitted with a one-component Drude or extended-Drude model. The conductivity spectrum is then obtained from
the best fit of a “double-damping Drude” model to reflectivity spectra, itself derived from the factorized form of the dielectric
function, and by a Kramers-Kronig inversion as well. The data and their analysis give a new insight of the 2D character of
the system.
Received 26 April 2001 and Received in final form 28 August 2001 相似文献
3.
D. Jacquemart J.-Y. Mandin V. Dana N. Picqué G. Guelachvili 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):55-69
To deduce accurate infrared molecular line parameters (positions at zero pressure, pressure-shifting and pressure-broadening
coefficients, collisional narrowing coefficients, and intensities) from rovibrational spectra, an automatic method based upon
a multispectrum fitting procedure has been set up, able to treat simultaneously several laboratory Fourier transform spectra.
A validation of this method, using absorption spectra of the 3-0 vibrational band of CO around 6 350 cm-1, already used to measure line intensities and self-broadening coefficients, is presented, and the advantages of the method
are pointed out. The self-collisional narrowing of CO was observed and determined for the first time in Fourier transform
spectra: β
= 0.028±0.004 cm-1 atm-1 at about 296 K.
Received 21 September 2000 and Received in final form 15 January 2001 相似文献
4.
P. Boubert P. Vervisch 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(1):43-48
Excitation of carbon monoxide molecules has been carried out in a cold cell and in a low-pressure plasma jet using an ArF
narrow-band excimer laser. The different excitation models are discussed and the relevance of atomic carbon absorption into
the laser cavities is pointed out. Excitation spectra of Cameron bands have been obtained in a room-temperature cell and compared
with calculated spectra. A value of the constant σ related to the interaction strength between a
3
Π(
v
= 2) state and its neighbouring singlet states is derived: 0≤σ≤0.05. The fluorescence spectrum following broad band excitation of CO has been observed both in UV and visible. Similar experiments
carried out in a high enthalpy flow have allowed to point out the presence of a
3
Π metastable carbon monoxide. A method for relative measurements of this species concentration is proposed.
Received 9 April 2001 and Received in final form 13 June 2001 相似文献
5.
W. Plank T. Pichler H. Kuzmany O. Dubay N. Tagmatarchis K. Prassides 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,17(1):33-42
Raman spectra are presented for the single bonded dimeric fullerene (C
60
-
)
2
and compared to optical spectra and Raman spectra of the isostructural and isoelectronic heterofullerene (C59N)2. The spectra of both materials exhibit strong correlations with respect to splitting, line position, and line intensity.
This holds for non resonant excitation with blue and green lasers as well as for the strong resonances observed with red lasers.
The latter observation is consistent with a downshift for the electronic transition energies as compared to C60. The absorption edge of thin films of (C59N)2 was found at 1.4 eV. The three intercage modes were observed at 82, 103, and 111, and at 88, 98, and 106 cm-1 for (C59N)2 and (C
60
-
)
2
, respectively. A surprising difference was found for the position of the pentagonal pinch modes in the two materials as they
were observed at 1461 and at 1451 cm-1, for (C59N)2 and (C
60
-
)
2
, respectively. This is interpreted as a consequence of some characteristic differences in the electronic structure of the
two compounds.
Received 25 January 2000 and Received in final form 10 April 2000 相似文献
6.
J. Valenta J. Dian K. Luterová P. Knápek I. Pelant M. Nikl D. Muller J. J. Grob J. -L. Rehspringer B. Hönerlage 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(3):395-398
Silicon nanocrystals were prepared by Si+-ion implantation and subsequent annealing of SiO2 films thermally grown on a c-Si wafer. Different implantation energies (20-150 keV) and doses - cm
-2
) were used in order to achieve flat implantation profiles (through the thickness of about 100 nm) with a peak concentration
of Si atoms of 5, 7, 10 and 15 atomic%. The presence of Si nanocrystals was verified by transmission electron microscopy.
The samples exhibit strong visible/IR photoluminescence (PL) with decay time of the order of tens of μs at room temperature.
The changes of PL in the range 70-300 K can be well explained by the exciton singlet-triplet splitting model. We show that
all PL characteristics (efficiency, dynamics, temperature dependence, excitation spectra) of our Si+-implanted SiO2 films bear close resemblance to those of a light-emitting porous Si and therefore we suppose similar PL origin in both materials.
Received 1st September 1998 and Received in final form 7 September 1999 相似文献
7.
A detailed Raman study on thin single-wall carbon nanotubes prepared by the HiPCO process 总被引:2,自引:0,他引:2
A. Kukovecz Ch. Kramberger V. Georgakilas M. Prato H. Kuzmany 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(2):223-230
The Raman spectrum of single wall carbon nanotubes (SWNTs) prepared by high pressure CO decomposition (HiPCO process) has
been recorded at nine excitation laser energies ranging from 1.83 eV to 2.71 eV. The characteristic nanotubes features: G
band, D band and radial breathing mode (RBM) have been analyzed and compared to those of an arc discharge SWNT material of
similar diameter. A strong Breit-Wigner-Fano type (metallic) contribution to the G band was found in the spectra measured
with green lasers, while spectra measured with red lasers indicate resonances of semiconducting SWNTs. Analysis of the energy
dependence of the position of the D band revealed sinusoid oscillations superimposed on a linear trend. The validity of full
DOS calculations for HiPCO materials has been confirmed by a match found between the estimated spectral contribution of metallic
SWNTs as calculated from the components of the measured G band and as predicted by the (n, m) indexes of the major scatterers of DOS simulations. The RBM region of the HiPCO spectrum is more complex than usually observed
for SWNTs. The analysis performed with a Gaussian distribution and improved fitting parameters leads to a mean diameter and
variance of 1.05 nm and 0.15 nm, respectively. A bimodal Gaussian distribution had little influence on the error sum but reduced
the standard error slightly. The major spectral features of the RBM could be interpreted using available resonance Raman theory.
Received 5 February 2002 / Received in final form 3 April 2002 Published online 19 July 2002 相似文献
8.
F. Edery A. Kanaev 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(2):257-264
We have carried out experiments of two-photon excitation of vapor phase H2O and D2O molecules at atmospheric pressure. A narrow-band tunable UV OPO laser is used in the experiments. Transient
B
1
→
B
1
emission from the excited predissociating state is seen in both cases. The complete
B
1
←
A
1
fluorescence excitation spectrum in the spectral range of 245-250 nm is measured and compared with theory. It is shown that
the predissociation rate increases with the rotational quantum number K'
a
> 2 more strongly than with K
′2
a
. No perturbation effects on the measured LIF spectra are observed at a laser power density below 2 GW/cm2. Experimental results indicate a negligible contribution from both molecular association and collisions with atmospheric
gases. Only an extremely weak vibrational progression belonging to the second positive system of N2 has been observed, which appears to be due to energy and charge transfer in N
+
2
*
+
H
2
O collisions.
Received 25 January 2002 / Received in final form 27 May 2002 Published online 4 March 2003 相似文献
9.
Chen Guo-xin P.P. Ong 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,6(2):153-156
Relativistic distorted-wave method was used to calculate the electron impact excitation collision strengths for transitions
2
s2
1
S0-2
s
2
p
3
P1 of Be-like isoelectronic ions. The target states were described, respectively, by 10-level, 46-level and 133-level MCDF configuration-expansion.
The relativistic continuum orbitals were calculated in the potential field of frozen target-ion charge distribution with semi-classical
exchange potential. The influence of the target states on this collision process along the isoelectronic sequence was investigated
in the above three MCDF configuration-expansion modes. It was found that the configurations in the n
=3 and the n
=4 complexes have great influence on both the high and the low Z ions but the influence is relatively small for intermediate Z ions. The latter phenomenon was attributed to competition between opposing correlation and relativistic effects on the collision
strengths.
Received: 25 February 1998 / Received in final form: 18 June 1998 相似文献
10.
A. Furrer H.-U. Güdel 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(1):81-84
The inelastic neutron scattering technique was employed to study the magnetic excitation spectra in the diluted one-dimensional
Heisenberg antiferromagnet CsMn1-xMgxBr3 (x
=0, 0.05, 0.10, 0.25, 0.50). The spectral response is interpreted in terms of spin-wave excitations in finite chain segments
of Mn2+ ions, which are found to exist as long as the chain length exceeds twice the wavelength of the spin excitation. This limit
determines the crossover into the mesoscopic regime.
Received 31 December 1999 相似文献
11.
C. Gerth B. Kanngießer M. Martins P. Sladeczek K. Tiedtke P. Zimmermann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(1):65-69
The resonances of atomic Lu have been investigated by photoelectron and photoion spectroscopy using monochromatized synchrotron
radiation in the vacuum ultraviolet energy region. The total photoion yield has been compared to calculations in which the
extended Fano theory (Mies formalism) and the Hartree-Fock method were applied. The resonance structure is dominated by the
spin-orbit splitting of the 5p core hole. In the photoion yield spectra of singly and doubly charged ions a high fraction of Lu2+ ions has been found in the region of the 5p
-1
(2
P
1/2
)nd resonances. Photoelectron spectra, recorded in this resonance region, have been investigated with respect to deexcitation
channels connected with Lu2+ ions. The 5p
-1
(2
P
1/2
)nd resonances predominantly autoionize by spin-flip into states, which decay in the second step into Lu2+ final ionic states.
Received: 2 September 1998 / Accepted: 17 September 1998 相似文献
12.
N. Petit F. Gervais P. Buvat P. Hourquebie P. Topart 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,12(3):367-372
The reflectivity spectrum of a polyaniline CSA-doped in presence of m-cresol has been measured over the wide wavenumber range
of 15- 9 000 cm
-1 (0.002-1.1 eV) at room temperature. Experimental data compare well with similar experiments performed by another group. The
conductivity spectrum of this conducting polymer has been deduced from the reflectivity spectrum by means of two methods,
Kramers-Kronig transformation and best fit of an “extended Drude” model to the reflectivity spectrum. Whereas the deviation
from Drude behavior was interpreted in terms of Anderson localization or by inhomogeneous disorder by other groups, it is
shown here that a different model developed for conducting oxides that also exhibit non-Drude behavior, applies very well
to this example of conducting polymer.
Received 11 February 1999 and Received in final form 26 April 1999 相似文献
13.
During the last decade, infrared optical sum-frequency generation (SFG) has been demonstrated to be a valuable technique for
acquiring vibrational spectra of molecules at interfaces. However, the instrumentation that most frequently has been employed,
which is based upon picosecond-scale pulse-width lasers, is fundamentally limited in the spectral resolution that can be achieved
(typically ∼6 cm-1). We have optimized an older technology, based on a nanosecond-scale pulse-width laser, which enables the infrared frequency
to be specified to within 0.2 cm-1. Exploiting this advantage, we have observed previously unrecognized features in the SFG spectrum of self-assembled monolayers.
We demonstrate this through experiments performed on rubbed octadecylsiloxane (ODS) on glass, a system of considerable importance
in liquid-crystal-display technology.
Received: 14 August 2001 / Revised version: 15 January 2002 / Published online: 14 March 2002 相似文献
14.
O. Wilhelmi K.-H. Schartner 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(1):79-90
Molecular oxygen O2 was dissociated in collisions with protons and electrons in the intermediate velocity range (p+-energies: 17-800 keV, e--energies: 0.2-2 keV). Fluorescence from excited atomic and singly ionised fragments and from singly ionised molecules was
detected in the VUV and in the visible and near UV spectral range. Highly resolved spectra are presented for the VUV (46-131
nm) and the near UV/visible (340-605 nm) spectral range. Absolute emission cross-sections have been determined for dissociative
ionisation and excitation leading to fluorescence in the VUV. Results are compared with published data.
Received 9 September 1999 and Received in final form
15 December 1999 相似文献
15.
A. Kanaev L. Museur F. Edery T. Laarmann T. Möller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(2):261-268
We have studied the fluorescence of electronically excited OH*, H* and H2O+* dissociation fragments after VUV excitation ( h
ν≥11.6
eV) of rare-gas clusters (Rg = Ne, Ar) doped with H2O molecules. In contrast to a free molecule, where Balmer H-series dominate the UV-visible spectra, only the OH
*
(
A
2
Σ
+
↦
X
2
Π) emission band is observed in neon clusters. No emission of excited water ions has been observed. We find that while higher
excitation energies (Ne vs. Ar) induce higher vibrational excitation of the OH*
(
A
) fragment, the rotational temperature is lower. This effect is attributed to the difference in the geometric position of the
H2O molecule on the surface or inside the Rg-cluster. The rotational relaxation in neon clusters is rapid while the vibrational
relaxation is slow because of the coupling with the low energy matrix phonons.
Received 7 March 2002 / Received in final form 27 May 2002 Published online 19 July 2002 相似文献
16.
M.A. Gaveau M. Briant P.R. Fournier J.M. Mestdagh J.P. Visticot F. Calvo S. Baudrand F. Spiegelman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(2):153-161
Spectroscopic experiments have been performed, providing emission and excitation spectra of calcium atoms trapped on argon
clusters of average size 2 000. The two experimental spectra fall in the vicinity of the calcium resonance line 1P 1 → 1S0 at 422.9 nm. The excitation spectrum consists in two bands located on each side of the resonance line of the free calcium.
In addition, Monte Carlo calculations, coupled to Diatomics-In-Molecule potentials are employed to simulate the absorption
spectrum of a single calcium atom in the environment of a large argon cluster of average size 300. The theoretical absorption
spectrum confirms the existence of two bands, and shows that these bands are characteristic of a calcium atom located at the
surface of the argon cluster and correspond to the excited 4p orbital of calcium either perpendicular or parallel to the cluster surface. The precise comparison between the shape of the
absorption spectrum and that of the fluorescence excitation spectrum shows different intensity ratios. This could suggest
the existence of a non adiabatic energy transfer that quenches partly the fluorescence of trapped calcium. Another explanation,
although less likely, could be a substantial dependence of the calcium oscillator strength according to the alignment of the
calcium excited orbital with respect to the cluster surface. The emission spectrum always shows a band in the red of the resonance
line which is assigned to the emission of calcium remaining trapped on the cluster. When exciting the blue band of the excitation
spectrum, the emission spectrum shows a second, weak, component that is assigned to calcium atoms ejected from the argon clusters,
indicating a competition between ejection and solvation.
Received 7 May 2002 Published online 1st October 2002
RID="a"
ID="a"e-mail: jmm@drecam.saclay.cea.fr
RID="b"
ID="b"URA 2453 du CNRS
RID="c"
ID="c"UMR 5626 du CNRS 相似文献
17.
F. Gervais N. Petit C. Popon P. Buvat 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):47-52
The reflectivity spectrum of a polyaniline CSA-doped in presence of m-cresol has been measured over the wide wavenumber range
25-15,000 cm-1 (0.003-1.9 eV) for three different doping levels. Since spectra cannot be fitted correctly with the conventional Drude model,
several extensions are tested. A model derived from the factorized form of the dielectric response and including the effect
of Anderson localization in disordered metals, is proposed and found to yield good fit to data with a satisfactory physical
meaning. Data are reduced to a small number of parameters potentially useful for further comparison with other conducting
polymers or even other non-Drude conducting media like oxides.
Received 6 February 2002 / Received in final form 12 August 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: gervais@delphi.phys.univ-tours.fr
RID="b"
ID="b"UMR 6157 CNRS/CEA 相似文献
18.
19.
M. Snels G. D'Amico 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(2):137-142
High resolution infrared spectra (0.001 cm-1) have been measured for mixtures of 1-chloro-1,1-difluoroethane in Ne, expanded in a supersonic planar jet. The ν
7
fundamental has been analyzed for both isotopic species, CH3CF2
35Cl and CH3CF2
37Cl. A weak b-type component has been observed for the first time.
Received 20 May 2002 / Received in final form 10 July 2002 Published online 24 September 2002
RID="a"
ID="a"Also: Dipartimento di Scienze Fisiche Universitá di Napoli “Federico II” Complesso Universitario di M.S. Angelo, 80126 Napoli,
Italy. e-mail: m.snels@isac.cnr.it 相似文献
20.
P. Guazzoni M. Jaskola L. Zetta J.N. Gu A. Vitturi G. Graw R. Hertenberger P. Schiemenz B. Valnion U. Atzrott G. Staudt 《The European Physical Journal A - Hadrons and Nuclei》1998,1(4):365-378
The (p,α) reaction on 90Zr has been studied in a high resolution experiment at an incident proton energy of 22 MeV. The cross section and asymmetry
angular distributions for transitions to 36 levels of 87Y with an excitation energy up to 3 MeV have been measured. DWBA analyses of experimental angular distributions, using either
Woods-Saxon or Double Folded potentials for the exit channel, have been done, allowing either the confirmation of previous
spin and parity values or the assignment of new spin and parity to a large number of states. The structure of low lying states
of 87Y has been studied in the framework of the shell model, using the OXBASH code. With the interaction PMM90 reasonable agreement
is obtained for part of the negative parity spectrum.
Received: 17 November 1997 相似文献