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1.
S. P. Dmitriev N. A. Dovator R. A. Zhitnikov V. A. Kartoshkin V. D. Mel’nikov 《JETP Letters》1997,65(5):399-401
An experiment on the observation of spin polarization of metastable helium atoms interacting with optically oriented sodium
atoms under continuous rf discharge conditions is described. Laser radiation with alternating-sign circular polarization,
tuned to the resonance excitation of the 32
S
1/2–32
P
1/2 transition in Na atoms, is used as the source for optical pumping of ground-state sodium atoms.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 5, 385–387 (10 March 1997) 相似文献
2.
Using an atomic-absorption spectral analysis technique, we determined the concentrations of helium atoms in states 21S, 21P, 23S, and 23P in an atmospheric-pressure glow discharge in helium (99.98%) and in a mixture of helium with nitrogen (99.5%He+0.5%N2). It is shown that the population of the lower excited levels of helium atoms (n = 2) in its mixture with nitrogen is almost
an order of magnitude smaller than in the case of a discharge in helium. The maximum of the concentration of excited atoms
in a discharge both in helium and in its mixture with nitrogen is in the cathode region at a distance of about 0.1 mm from
the cathode. The reaction of quenching of excited helium atoms by nitrogen molecules is responsible for the sharp decrease
in the concentration of He(n = 2) on addition of nitrogen into helium.
Presented at the 5th Symposium on Physics and Diagnostics of Laboratory and Astrophysical Plasmas, Belarus, Serbia and Montenegro,
Minsk, Belarus, September 20–23, 2004; 12th International Congress on Plasma Physics, October 25–29, 2004, Nice, France.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 4, pp. 530–537, July–August, 2005. 相似文献
3.
O. A. Bukin I. V. Bazarov N. V. Bodin A. A. Il’in V. I. Tsarev A. Yu. Maior E. N. Bol’shakova 《Journal of Applied Spectroscopy》2000,67(2):320-326
This article reports the results of an experimental investigation of the basic mechanisms that cause the broadening of emission
lines of a laser-induced plasma generated on the surface of rigid targets in a gaseous atmosphere. The contribution of Stark
and resonance mechanisms of emission-line broadening for the resonance doublet Al I 3s23p2P3/2,1/2-3s24s2S1/2 and triplet Mg I 3s3p3P
0,1,2
0
-3s4s3S1 is discussed. The concentrations of neutral Al atoms in the laser-induced plasma are evaluated by the magnitude of resonance
line broadening.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 234–237, March–April, 2000. 相似文献
4.
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
5.
N. A. Borisevich A. P. Lugovskii V. A. Povedailo E. E. Tselesh D. L. Yakovlev 《Journal of Applied Spectroscopy》2010,77(3):343-348
Conformations of He-jet-cooled trimethyl[(3-indole)ethoxy]silane (TIES) have been studied using a laser spectroscopy technique
in combination with quantum-chemical computations. Six probable conformers of the molecule were computed, of which only two
conformations were observed. Based on an analysis of fluorescence excitation spectra, fluorescence spectra, shapes of rotational
band contours at the electronic S0–S1 transition of TIES, and theoretical computations, the above conformers were assigned to steric structures. Twisted structures
have the lowest energy due to intramolecular hydrogen bonds C - H ?O < CSi C - H \cdots O <_C^{Si} between hydrogen atoms of methyl groups and an oxygen atom and C–H···π between H and the π-electron cloud of the indole ring. 相似文献
6.
B.?Niermann M.?B?ke N.?Sadeghi J.?Winter 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(3):489-495
Space resolved concentrations of helium He* (3S1) and argon Ar* (3P2)
metastable atoms in an atmospheric pressure radio frequency micro-plasma jet were measured using tunable diode laser absorption
spectroscopy. Even small absorptions down to 10-4 could be measured using lock-in technique. The absolute density of metastable
atoms densities at different rf-power, flow rate and gas mixture was deduced from measured absorption rates. Metastable
concentrations range from 109 to 1011 cm-3. Analysis of spectral profiles provided the pressure broadening coefficients
of both metastable atoms by helium. The spatial distribution of metastable atoms in the plasma volume was obtained for various
discharge
conditions. Density profiles between the electrodes reveal the sheath structure and reflect the plasma excitation distributions
in the
discharge volume. It reveals the dominance of the α-mode discharge. 相似文献
7.
K. O. Korovin E. Heinecke A. Patzer T. Liebig O. S. Vasyutinskii D. Zimmermann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(1):57-63
The first determination of translational anisotropy parameters β in the
photodissociation of NaI molecules in the spectral range
315–370 nm is reported. The anisotropy parameters were
determined by the analysis of Doppler resolved absorption profiles of
Na(2S1/2) atoms produced in the photodissociation of NaI by
linearly polarized light. The profiles were recorded for two orientations of
the photolysis light: parallel and perpendicular to the direction of the
probe beam. The value of the parameter β was obtained from a simultaneous fit
of the profiles. The role of the rotation of the parent molecules on the
branching ratio between parallel and perpendicular transitions in NaI during
dissociation is discussed. 相似文献
8.
Chengying Xie Xiaohong Zhou Yuhu Zhang Yingxiang Guo Xiangguo Lei Yong Zheng Minliang Liu Litao Song Hualei Wang Haiping Yu Wentao Guo Peng Luo Zhijun Wu Lihua Zhu Xiaoguang Wu 《中国科学G辑(英文版)》2005,48(4):442-449
High-spin states in 190Tl have been studied via the 160Gd(35Cl, 5nγ) reaction. The level scheme, consisting of the πh
9/2⊗vi
13/2 oblate band and a cascade with character of single particle excitations, has been established. Spin values have been firmly
assigned to the oblate band in 190Tl, resulting in low-spin signature inversion in the πh
9/2⊗vi
13/2 oblate band for the first time. Based on the similarity of the level structure in doubly odd Tl nuclei, spin values for the
oblate bands in 192–200Tl should be re-assigned, and a consistent low-spin signature inversion has occurred in these oblate deformed nuclei. The
low-spin signature inversion phenomena can be interpreted qualitatively by using the 2-quasiparticle plus rotor model including
p-n residual interactions. 相似文献
9.
The polarization of helium 23
S
1 atoms is achieved by collisional processes involving optically oriented sodium atoms in a Na-He gas-discharge plasma, and
the conditions for observing the signal of the magnetic resonance excited by the 23
S
1 state of the He atoms are investigated.
Zh. Tekh. Fiz. 67, 131–133 (June 1997) 相似文献
10.
W. S. Miller C. V. Sulham J. C. Holtgrave G. P. Perram 《Applied physics. B, Lasers and optics》2011,103(4):819-824
A rubidium laser pumped on the 52S1/2–52P3/2 D2 transition by a pulsed dye laser at pump intensities exceeding 3.5 MW/cm2 (>1000 times threshold) has been demonstrated. Output energies as high as 12 μJ/pulse are limited by the rate for collision
relaxation of the pumped 2P3/2 state to the upper laser 2P1/2 state. More than 250 photons are available for every rubidium atom in the pumped volume during each pulse. For modest alkali
atom and ethane spin–orbit relaxer concentrations, the gain medium can only process about 50 photons/atom during the 2–8 ns
pump pulse. At 110°C and 550 Torr of ethane, the system is bottlenecked in the 2P3/2 state and all of the incident photons cannot be absorbed. The output energy is linearly dependent on pump pulse duration
for a given pump energy. The highly saturated pump limit of the recently developed three-level model for diode pumped alkali
lasers (DPALs) is developed. The system efficiency based on absorbed photons approaches 36% even for these extreme pump conditions. 相似文献
11.
F. Kottmann W. Amir F. Biraben C. A. N. Conde S. Dhawan T. W. Hänsch F. J. Hartmann V. W. Hughes O. Huot P. Indelicato L. Julien P. Knowles S. Kazamias Y.-W. Liu F. Mulhauser F. Nez R. Pohl P. Rabinowitz J. M. F. dos Santos L. A. Schaller H. Schneuwly W. Schott D. Taqqu J. F. C. A. Veloso 《Hyperfine Interactions》2001,138(1-4):55-60
A measurement of the 2S Lamb shift in muonic hydrogen (μ−p) is being prepared at the Paul Scherrer Institute (PSI). The goal of the experiment is to measure the energy difference
ΔE(25
P
3/2−23
S
1/2) by laser spectroscopy (λ≈6μm) to a precision of 30 ppm and to deduce the root mean square (rms) proton charge radius with
10−3 relative accuracy, 20 times more precise than presently known.
An important prerequisite to this experiment is the availability of long-lived μp2S
-atoms. A 2S-lifetime of ∼1 μs – sufficiently long to perform the laser experiment – at H2 gas pressures of 1–2 hPa was deduced from recent measurements of the collisional 2S-quenching rate. A new low-energy negative muon beam yields an order of magnitude more muon stops in a small low-density gas
volume than a conventional cloud muon beam. A stack of ultra-thin carbon foils is the key element of a fast detector for keV-muons.
The development of a 2 keV X-ray detector and a 3-stage laser system providing 0.5 mJ laser pulses at 6 μm is on the way.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
In terms of the adiabatic theory of interactions, we consider the results of the theoretical estimation of the rate constants
K
ST
of the nonradiative intersystem crossing conversion S
1(ππ*) ⇝ T
1
S
(ππ*) for nine aromatic molecules containing 10–14 carbon atoms and one or two heavy (many-electron) oxygen or chlorine atoms. 相似文献
13.
Iron diffusion in GaAs at arsenic pressure 1 atm is studied. The temperature dependences of the diffusion coefficient and
solubility of electrically active iron atoms in GaAs are determined. The dependences can be described by the Arrhenius equations
with the following parameters: D
0 = 1.61 cm2/s and E = (2.16 ± 0.47) eV (for diffusion) and N
S
0 = 4.62 ⋅ 1023 cm−3 and E
S
= (1.61 ± 0.16) eV (for solubility). The results obtained are compared with the earlier published data. The concentration
of electrically active iron atoms is shown to be about 2 times lower than the total iron concentration in GaAs.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 39–41, November, 2008. 相似文献
14.
A. Krämer M. L. Elidrissi-Moubtassim C. Bousquet J. Olivier-Fourcade J. -C. Jumas J. L. Tirado 《Il Nuovo Cimento D》1996,18(2-3):237-241
Summary We present here a study carried out on In16Sn4S32 and In16Fe8S32 spinels. Electronic and local environment changes of Sn and Fe are discussed from recorded M?ssbauer parameters. In the case
of the tin thiospinel, a reduction process from SnIV to SnII is obvious till an amount of 8 inserted Li. For the iron thiospinel a migration of iron atoms from the octahedral to the
tetrahedral sites is observed. In the region of higher lithium amounts (10– Li), in both spinels a further environment appears
indicating an increase of covalency.
Paper presented at ICAME-95, Rimini, 10–16 September 1995. 相似文献
15.
A measurement of the 2S1/2–2P3/2 (fine structure–Lamb shift) transition in N6+ is under way. The technique involves fast beam spectroscopy with a transverse interaction geometry and uses an isotopic CO2 laser and a resonant build up cavity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
R. Mosimann D. Haertle M. Jazbinsek G. Montemezzani P. Günter 《Applied physics. B, Lasers and optics》2006,83(1):115-119
We determined high absorption constants of crystals from photocurrent measurements within the interband absorption region
(10–104 cm-1). The method has been demonstrated in the interband absorption regime near 530 nm in Sn2P2S6, a novel infrared sensitive photorefractive material, and in the interband absorption regime near 257 nm of near stoichiometric
LiTaO3. Besides the verification of older measurements with our new technique, precise absorption data for Sn2P2S6 in the wavelength range 488–514 nm are presented.
PACS 42.70.Nq; 72.41.+w; 78.20.Ci 相似文献
17.
The unit cell of triglycine sulfate (TGS) contains the following glycine ions: dimers (GIISHBGIII)+ with a short hydrogen bond (SHB) and a monomer (SO4LHBGI)+ with a long hydrogen bond (LHB) to the SO4
2− anion. The spontaneous polarization results from a statistical charge distribution and the Coulomb interaction between SO4
2− and fast rotating –NH3
+ groups. In the lamellar model, chains of –SO4–(GIISHBGIII)–SO4–(GIISHBGIII)–SO4 lying along the polar b-axis are linked perpendicularly to this axis by SO4LHBGI+ units. Tilting the LHBGI+ ion around the axis in the mirror plane decides on the direction of the charge displacement from this symmetry plane. The
reversal of the spontaneous polarization, i.e., −P
S↔ +P
S, is related to the rotation of the NH3 group. If this rotation becomes slowed down at low temperature and/or under high pressure, the coercive field increases dramatically.
Application of an external electric field E
⊥ perpendicular to the b-axis leads to a hysteresis loop of the polarity P(E), and finally to its disappearance. This phenomenon comes from an ordering of protons in hydrogen bonds perpendicular to
the polar axis. This is the first study of the E
⊥ effect by nuclear magnetic resonance.
Authors' address: Jan Stankowski, Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, Poznań 60-179,
Poland 相似文献
18.
K. Naveedullah 《Il Nuovo Cimento D》1987,9(12):1463-1466
Summary The broadening and shift of thallium 6P
1/2–10P
1/2,3/2 transitions perturbed by argon and helium gas have been measured by two-photon Doppler-free absorption and ionization detection.
Broadening and shift coefficients for He+Tl and Ar+Tl are obtained and van der Waal constants are determined.
Riassunto L’allargemento e lo spostamento delle transizioni 6P 1/2–10P 1/2,3/2 del tallio disturbate dai gas argon ed elio sono statimisurrrati da un’osservazione di assorbimento e ionizzazione in assenza di effetto Doppler a due fotoni. Si ottengono i coefficienti di allargamento e spostamento per He+Tl e Ar+Tl e si determinano le costanti di van der Waals.
Резюме Измеряются уширение и сдвиг 6P 1/2–10P 1/2,3/2 переходов в таллии, возмущенном аргоном и гелием. Получаются козффициенть уширения и сдвита для He+Tl и Ar+Tl. Определяются постояннйе ван дер Ваальса.相似文献
19.
N. B. Éshkobilov 《Journal of Applied Spectroscopy》2000,67(2):343-345
An investigation has been made of the3P0,1,2-series of Zn (n=17–60), Cd (17–50), and Hg (18–60) atoms by the method of laser three-step photoionization. The energy (En) values and quantum defects (Δ) of these states are determined. The ionization potentials of the atoms are refined by matching
the convergence of the Rydberg series.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 249–250, March–April, 2000. 相似文献
20.
J. Mahoney W. Zhu V. S. Johnson K. H. Becker J. L. Lopez 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(3):441-447
We report a capillary dielectric barrier discharge (Cap-DBD) plasma operated in atmospheric pressure air. The plasma reactor
consists of metal wire electrodes inside quartz capillary tubes powered with a low kilohertz frequency AC high voltage power
supply. Various reactor geometries (planar, 3-D multilayer, and circular) with wall-to-wall separation ranging from zero up
to 500 micron were investigated. For the electrical and spectral measurements, three reactors, each with six tubes, six inches
in length, were assembled with gap widths of 500 micron, 225 micron, and 0 micron (i.e. tubes touching). The discharges appear
homogenous across the whole device at separations below 225 micron and turned into filamentary discharges at larger gap spaces.
The operating voltage was generally around 3–4 kV (rms). The power consumption by the Cap-DBD was calculated using voltage/charge
Lissajous figures with observed powers of a few watts to a maximum of about 14 W for the reactor with no gap spacing. Further
studies of optical emission spectroscopy (OES) were employed to evaluate the reactive species generated in the microplasma
source. The observed emission spectrum was predominantly within the second positive system of
N2\mbox{N}_2(C3\mbox{C}^3
Pu\Pi_u–B3\mbox{B}^3
Pg\Pi_g) and the first negative system of
N+2\mbox{N}^+_2(B2\mbox{B}^2
S+u\Sigma^+_u–X2\mbox{X}^2
S+g\Sigma^+_g). 相似文献