共查询到20条相似文献,搜索用时 31 毫秒
1.
K. J. Öberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(1):25-47
Transition isotope shifts of 3s–3p transitions in Ne II and Ne III are measured in Fourier transform spectra from a hollow-cathode
source. Accurate absolute line-center positions of the 20Ne isotope are derived for the purpose of tertiary wavelength standards in the region 2000–5000 ?. A robust statistical treatment
is applied, yielding line-position uncertainties that are lower than for the Ar II secondary standards used as references.
The influence of Stark shifts on both the new Ne II standards and the Ar II standards is also investigated. In addition, improved
wavenumbers of the 3p–3d and 3p–4s transitions are presented, of which 12 in Ne II have been measured for the first time.
Electronic supplementary material Supplementary Online Material 相似文献
2.
A. Adamczak J. Gronowski 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):493-497
The diffusion radius of the 1S muonic hydrogen atoms in gaseous
H2 targets with various deuterium admixtures has been
determined for temperatures T=30 and 300 K. The Monte Carlo
calculations have been performed using the partial differential cross
sections for pμ and dμ atom scattering from the molecules
H2, HD and D2. These cross sections include
hyperfine transitions in the muonic atoms, the muon exchange between
the nuclei p and d, and rotational-vibrational transitions in the
target molecules. The Monte Carlo results have been used for preparing
the time-projection chamber for the high-precision measurement of the
nuclear μ- capture in the ground-state pμ atom, which is
now underway at the Paul Scherrer Institute. 相似文献
3.
T. Iino K. Ohashi K. Inoue K. Judai N. Nishi H. Sekiya 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):37-40
Vibrational spectra of mass-selected
Ag+(H2O)n ions are measured by infrared photodissociation
spectroscopy and analyzed with the aid of density functional theory
calculations. Hydrogen bonding between H2O molecules is found to be
absent for cold Ag+(H2O)3, but detected for
Ag+(H2O)4 through characteristic changes in the position and
intensity of OH-stretching transitions. The third H2O coordinates
directly to Ag+, but the fourth H2O prefers solvation through
hydrogen bonding. The preference of the tri-coordinated form is attributed
to the inefficient 5s–4d hybridization in Ag+, in contrast to the
efficient 4s–3d hybridization in Cu+. For Ag+(H2O)4,
however, di-coordinated isomers are identified in addition to the
tri-coordinated one. 相似文献
4.
C.Q. Chen R. Helbig F. Engelbrecht J. Zeman 《Applied Physics A: Materials Science & Processing》2001,72(6):717-720
We performed infrared absorption measurements on 4H-SiC samples with polarization E∥c and E⊥c at 8, 85 and 300 K. From the
strong temperature dependence of the absorption lines, electronic transitions are separated from vibronic transitions. The
electronic transition lines between 300 and 500 cm-1 are assigned to the shallow nitrogen donor. It is found that the electronic transitions of the shallow nitrogen donor are
polarization dependent. Zeeman spectroscopy was performed to study the influence of the magnetic field on the electronic transitions
up to 15 T. The results show no linear Zeeman splitting and only a diamagnetic shift. This is consistent with the effective
mass tensor of three different diagonal components in 4H-SiC.
Received: 25 November 1999 / Accepted: 20 April 2000 / Published online: 2 August 2000 相似文献
5.
B. Viaris de Lesegno J.C. Karam M. Boustimi F. Perales C. Mainos J. Reinhardt J. Baudon V. Bocvarski D. Grancharova F. Pereira Dos Santos T. Durt H. Haberland J. Robert 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):25-34
A new Stern Gerlach interferometer operating with a nozzle beam of metastable argon atoms Ar* (3p5 4s, 3
P
2) is described. The selection of incoming (polarisation) and outgoing (analysis) Zeeman sublevels is achieved by use of laser
induced transitions at two wavelengths, 811.5 nm (closed J = 2 → J = 3 transition) and 801.5 nm (open J = 2 → J = 2 transition). Linear superpositions of Zeeman sublevels, just beyond the polariser and just before the analyser, are prepared
by means of two zones where Majorana transitions take place. In between, a controlled magnetic field configuration (the phase
object) is produced within a triple μ-metal shielding. Standard interference patterns are obtained by scanning the field and
detecting the atoms by secondary electron emission from a Faraday cup. When a static radial magnetic gradient is used, the
beam profile is modulated by interference. The transverse pattern, which can be translated at will by adding a homogeneous
field, is observed for the first time using a multi-channel electron multiplier followed by a phosphor screen and a CCD camera.
The results satisfactorily agree with all theoretical predictions.
Received 27 June 2002 / Received in final form 20 September 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: perales@lpl.univ-paris13.fr
RID="b"
ID="b"UMR 7538 du CNRS 相似文献
6.
J. S. Bakos G. P. Djotyan P. N. Ignácz M. Á. Kedves M. Serényi Zs. Sörlei J. Szigeti Z. Tóth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(1):141-149
The displacement of Rb atoms in a magneto-optical trap (MOT) caused by the force of a finite time series of counter-propagating
frequency modulated light pulse pairs is measured as a function of the chirp of the pulses. The frequency modulated light
pulses induced 85Rb 52S1/2 F=3 ↔ 85Rb 52P3/2 F'=2, 3, 4 excitation and de-excitation of the atoms. The result of this excitation
de-excitation process is a force causing the acceleration and, consequently, the displacement of the maximum of the spatial
distribution of the trap atoms. The time dependence of the populations of the levels of the atom are calculated — including
also the 85Rb 52S1/2 F=2 and F'=1 states — as
the result of the interaction with the finite train of counter propagating frequency modulated light pulses by the solution
of the Bloch equations. As the result of the measurement the interval of the chirp of the frequency modulated light of given
intensity where the transitions take place, are determined. The results of the experiment and the expectation on the basis
of model calculations are in qualitative agreement. 相似文献
7.
D. Hojman J. Sauvage B. Roussière M. A. Cardona G. Marguier A. Wojtasiewicz J. Genevey A. Gizon F. Ibrahim A. Knipper F. Le Blanc J. Obert J. Oms 《The European Physical Journal A - Hadrons and Nuclei》2007,33(2):193-212
Low-spin states of 182Ir were populated through the β+ /EC decay of 182Pt . Two strong E2 transitions were observed for the first time: a 25.7keV transition in 182Ir and a 34.0keV transition in Re of probable mass A = 178 . Spin and parity, I
π = 3+ , are firmly assigned to the 182Ir ground state (g.s.). For the excited states, the parity is established and the spin determined or restricted. These assignments
support most of the interpretations of the level structure previously suggested. The systematics for the known 5+ → 3+ transitions in π h
9/2 ⊗ ν 1/2-[521] bands is presented. Using a semi-microscopic two-quasiparticle axial-rotor coupling model, particle configurations have
been attributed or suggested for most of the coupled states lying at low energy in 182Ir . 相似文献
8.
Excited state absorption and stimulated emission of Nd3+ in crystals. Part 2: YVO4, GdVO4, and Sr5(PO4)3F 总被引:1,自引:0,他引:1
L. Fornasiero S. Kück T. Jensen G. Huber B.H.T. Chai 《Applied physics. B, Lasers and optics》1998,67(5):549-553
3+ ion in the crystals YVO4, GdVO4, and Sr5(PO4)3F. The measurements were performed in the spectral region of the main laser transitions 4F3/2→4I9/2, 4F3/2→4I11/2, and 4F3/2→4I13/2by a continuous wave pump and probe technique. The calibrated gain and ESA spectra are presented and possible implications
of ESA on the laser performance are estimated. It is shown that ESA can be a small loss factor to the laser emission near
1060 nm but does considerably diminish the effective emission cross sections near 1340 nm especially in Nd:YVO4 and Nd:GdVO4.
Received: 29 January 1998/Revised version: 8 May 1998 相似文献
9.
C. Schumacher K. Jessen P. von Brentano A. Dewald M. Eschenauer H. Grawe J. Heese K.H. Maier M. Philipp E. Radermacher R. Schubart O. Stuch M. Wilhelm 《The European Physical Journal A - Hadrons and Nuclei》1998,2(3):233-236
The high-spin states of 147Tb have been studied with regard to their spins. The data were obtained by in-beam γ-ray spectroscopy using the reaction 120Sn(31P,4n)147Tb at 152 MeV performed at the Osiris spectrometer in Berlin. We obtained multipole mixing ratios for 60 transitions, and
level spins up to 67/2ħ are introduced.
Received: 30 March 1998 相似文献
10.
J. S. Bakos G. P. Djotyan P. N. Ignácz M. Á. Kedves M. Serényi Zs. Sörlei J. Szigeti Z. Tóth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,37(1):59-66
The spatial displacement of the 85Rb atoms in a
Magneto-Optical Trap (MOT) under the influence of series of frequency
modulated light pulse pairs propagating opposite to each other is measured
as a function of the time elapsed after the start of the pulse train, and
compared with the results of simulations. Adiabatic excitation and
consecutive de-excitation take place between the ground
52S1/2 (F=3) and the 52P3/2 (F'=2, 3, 4) excited levels as the result of
the interaction. The displacement of the 85Rb atoms is calculated as
the solution of simple equation of motion where the expelling force is that
arising from the action of the frequency modulated light pulses. The
restoring and friction forces of the MOT are taken into account also. The
system of Bloch equations for the density matrix elements is solved
numerically for transitions between six working hyperfine levels of the atom
interacting with the sequence of the frequency modulated laser pulses.
According to these simulations, the momentum transferred by one pulse pair
is always smaller than the expected 2ħk, (1) where ħ is the Plank constant and
k=2π/λ where λ is the wavelength, (2) having a maximum
value in a restricted region of variation of the laser pulse peak intensity
and the chirp. 相似文献
11.
H. Hess K.R. Asmis T. Leisner L. Wöste 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):145-149
We present results on the ultrafast dynamics of mass-selected neutral Ag4 clusters using NeNePo (negative ion - neutral - positive ion) femtosecond pump-probe spectroscopy. One-color pump-probe spectra
of the Ag4
-/Ag4/Ag4
+ system measured at 385 nm and an internal cluster temperature of 20 K display a complex beat structure over more than 60
ps. The oscillatory structure is attributed to vibrational wave packet dynamics in an excited “dark" state of neutral Ag4. A dominant 740 fs wave packet period as well as wave packet dephasing and rephasing are observed in the spectra. Fourier
analysis of the spectra yields a group of frequencies centered around 45 cm-1 and an anharmonicity χ
e2νχ
eχ
e of 2.65 cm-1 for the active vibrational mode.
Received 30 November 2000 相似文献
12.
Space-time dispersion of graphene conductivity 总被引:1,自引:0,他引:1
L. A. Falkovsky A. A. Varlamov 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(4):281-284
We present an analytic calculation of the conductivity of pure graphene as a
function of frequency ω, wave-vector k, and temperature for the
range where the energies related to all these parameters are small in
comparison with the band parameter γ≃3 eV, but much larger than
the collision rate τ-1. The simple asymptotic expressions are given
in various limiting cases. For instance, the conductivity for kv0≪
T≪ω is equal to σ(ω,k)=e2/4ħ and independent
of the band structure parameters γ and v0. Our results are also
used to explain the known dependence of the graphite conductivity on
temperature and pressure. 相似文献
13.
R. M. Jennerich A. N. Keiser D. A. Tate 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):81-89
We have obtained Doppler-free spectra of transitions in the
→ 2p2(3P)
and
→
multiplets of atomic nitrogen using saturated absorption spectroscopy. These multiplets consist of
respectively of seven and eight transitions, and have center of gravity wavelengths of 821 nm and 869 nm. Values for the hyperfine
structure coupling constants of all the upper and lower states for these multiplets were obtained for both 14N and 15N. Isotope shifts of three transitions in each multiplet were also measured, and a significant J-dependence to the shifts
was observed. 相似文献
14.
K. J. Öberg H. Lundberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):15-34
Radiative lifetimes of nine out of the twelve 4f136p levels in Yb III have been measured, seven of these for the first time. A Penning discharge lamp is introduced as a continuous
plasma source, in which the lifetimes are determined with the time-resolved laser-induced fluorescence technique by pumping
from metastable 5d and 6s levels. Spectra of the same source are recorded with a Fourier-transform spectrometer, which are
used to derive branching fractions of the 6p and 7s levels. Combined with the lifetimes, the branching fractions are used
to determine 81 experimental transition probabilities. Wavelengths of 142 Yb III transitions are measured and the uncertainties
of corresponding Ritz wavenumbers are improved by an order of magnitude from the prior values. The energy of the 5d (5/2,5/2)○
0 level has been shifted 144.20 cm-1 to the higher value 45421.045 cm-1. Much emphasis is put on data treatment and error analysis.
Electronic supplementary material Supplementary Online Material 相似文献
15.
M. Asai K. Tsukada S. Ichikawa M. Sakama H. Haba Y. Nagame I. Nishinaka K. Akiyama A. Toyoshima T. Kaneko Y. Oura Y. Kojima M. Shibata 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):17-19
A new neutron-deficient berkelium isotope 241Bk produced in the 239Pu(6Li, 4n) reaction has been identified using a gas-jet coupled on-line isotope separator. Cm K and L X-rays associated with the EC decay of 241Bk were observed in the mass-241 fraction, and three γ transitions were attributed to the EC decay of 241Bk through X-γ coincidences. The half-life of 241Bk was determined to be 4.6±0.4 min which is 1/2-1/4 of that of theoretical predictions. The half-life value and the observed
γ transitions can be consistently explained as a consequence of the allowed EC transition of π7/2+[633] → ν7/2+[624].
Received: 14 October 2002 / Accepted: 6 November 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: asai@tandem.tokai.jaeri.go.jp
Communicated by J. ?yst? 相似文献
16.
H. P. Liu Z. G. Sun S. D. Hogan N. Q. Lou 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(3):357-362
We report an experimental study of the multiphoton dissociation dynamics of
CF3I performed on a home-built femtosecond laser pump-probe system, with
time-of-flight mass spectrometer. The first repulsive A band and the
5pπ37sσ υ2=1 Rydberg state of CF3I were accessed
by one- and two-photon transitions at 267 nm, respectively, with the latter
two-photon absorption followed by a further two-photon probe transition at
401 nm to the
state of the parent ion. The observed signals
from the CF3
+ and I+ fragments show similar multi-component
exponential decay patterns but the former is 4 times stronger than the
latter. However, the parent CF3I+ signal was observed to evolve in a
very different manner, decreasing sharply when probed in the first 289 fs
following excitation and subsequently rising again after 860 fs to a
constant level below that measured at negative pump-probe delay times when the
pump and probe pulses exchange roles. This dip observed in the parent ion
profile, is very different from that previously reported at shorter pump
wavelengths of 264 nm or 265 nm, and is interpreted as the competition
between two different ionization channels. One from the vibrationally excited
υ2=1 of the irradiated Rydberg state and the other from the
dissociative vibrational origin of the same electronic state which is
populated by internal vibrational relaxation. 相似文献
17.
M. L. Li S. J. Zhu S. D. Xiao X. L. Che Y. N. U Y. J. Chen H. B. Ding L. H. Zhu G. S. Li S. X. Wen X. G. Wu 《The European Physical Journal A - Hadrons and Nuclei》2006,28(1):1-4
High-spin states of 137La have been investigated with the reaction 130Te(11B, 4n) at a beam energy of 50MeV. The level scheme of 137La has been expanded with spin up to 33/2ℏ. Several new bands have been found in this nucleus. A band crossing in the band
based on the 17/2- level has been observed at a rotational frequency of ℏω ∼ 0.48MeV. From systematic comparison, this band crossing probably
originates from the alignment of protons. One of the bands with strong M1 transitions is proposed as a collective oblate band ( γ ∼ -60°). 相似文献
18.
G. Stenuit S. Michotte J. Govaerts L. Piraux 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):103-107
Theoretical and experimental magnetizations of lead nanowire arrays well below the superconducting transition temperature
Tc are described. The magnetic response of the array was investigated with a SQUID magnetometer. Hysteretic behaviour and phase
transitions have been observed in sweeping up and down the external magnetic field at different temperatures. The Meissner
and Abrikosov states were also experimentally observed in this apparently type-I superconductor. This fact brings to the fore
the non-trivial behaviour of the critical boundary κ
c ( = 1/ in bulk materials) between type-I and type-II phase transitions at mesoscopic scales. The time-independent Ginzburg-Landau
equations particularized to cylindrically symmetric configurations enable one to explain and reproduce the experimental magnetization
curves within 10% of error.
Received 16 January 2003 / Received in final form 27 March 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: stenuit@fynu.ucl.ac.be 相似文献
19.
Y. Toh S. Yamada A. Taniguchi Y. Kawase 《The European Physical Journal A - Hadrons and Nuclei》1999,4(3):233-238
The structure of 152Nd, produced via β− decay of 152Pr, has been investigated using γ-γ coincidence, γ-γ angular correlation, and β-γ-γ triple coincidence measurements. Praseodymium
activities were obtained by the thermal neutron fission of 235U and collected by the on-line isotope separator KUR-ISOL. Nineteen γ-rays and four excited states were newly found. The spins
of six exited states were determined and the parities of three of them were also deduced. The spin and parity of the 152Pr ground state, which were previously considered as 4−, are proposed to be 4+ by the present study.
Received: 19 October 1998 / Revised version: 22 December 1998 相似文献
20.
This paper reports the synthesis of high upconversion luminescent Gd2O3: Er3+, Yb3+ nanophosphor through optimized combustion route using urea as a reducing agent. The paper also reports the first observation
of upconversion emission bands extending upto the UV region (335, 366 and 380 nm) in Er3+–Yb3+ co-doped phosphor materials. The fuel to oxidizer ratio has been varied to obtain the maximum upconversion luminescence.
Three high intensity bands are found at 408, 523–548 and 667 nm due to the 4G11/2 → 4I15/2, 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively, along with the other bands. Input excitation power dependence has been studied for different transitions,
and the saturation effect and decrease in the slope of different transitions at higher input pump power has been explained.
Heat treatments of the samples show change in crystallite phase/size and relative upconversion luminescence intensities of
blue, green and red bands. The color of the phosphor emission has shown to be tunable with change in the crystal structure
as well as on excitation laser power and Er3+–Yb3+ concentration. The property of color tunability of the phosphor material has been used to record the fingerprint in different
colors. Also, the future prospect of the nanocrystalline phosphor material as a sensor for temperature, using FIR method,
has been explored. 相似文献