共查询到20条相似文献,搜索用时 281 毫秒
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实验中通过互组跃迁689 nm激光抽运形成三重态最低能态原子布居,引入688 nm激光改变三重态最低能态间的原子布居,利用抽运光与探测光空间分离的方法观测碱土金属锶原子的三重态能态间跃迁(5s6s)3S1 → (5s5p)3Pj(j=0,1,2)的吸收谱线,对应三条跃迁线的激光波段为679 nm, 688 nm和707 nm.探测三重态原子跃迁谱线可以用于锶原子冷却中再抽运光707 nm和679 nm激光频率的直接锁定,相比于通常利用的腔传递技术,可以把再抽运光频率锁定在原子跃迁谱线上,有利于提高锶原子冷却中俘获原子数目的长期稳定性. 相似文献
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本文从理论和实验上对Cs39D态Rydberg原子在弱电场作用下的Stark效应做了详细研究. 理论上利用数值方法计算了Cs原子39D态的Stark结构;实验上,采用两步激发超冷基态原子获得超冷Rydberg原子,通过场电离的方法获得了39D态的Stark光谱,测量获得α5/22,α5/20,α3/22和α3/20相应的极化率分别为:62(7),-146(13), 73(6) 和-106(20) MHz·V-2cm2,实验结果与理论相符合. 相似文献
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本文在多通道量子数亏损理论(MQDT)框架下,利用相对论多通道理论(RMCT),分别在冻结实近似、 考虑Δl=-1的偶极极化效应、Δl=+1的偶极极化效应、Δl=± 1的偶极极化效应、伸缩模效应以及同时考虑偶极极化效应和伸缩模效应等不同层次近似下,系统地计算了碱金属Li, Na, K, Rb, Cs和Fr七个里德伯系列的能级,即ns2S1/2, np2P1/2, np2P3/2, nd2D3/2, nd2D5/2, nf2F5/2 和nf2F7/2.计算结果表明,电子关联效应对碱金属原子的里德伯能级的影响很大.总的来说,偶极极化效应比伸缩模效应重要,而在偶极极化效应中, Δl = + 1的偶极极化效应比Δl = - 1的偶极极化效应重要.但对于Na的ns2S1/2,(nd2D3/2,nd2D5/2)里德伯系列的能级,和Li的(np2P1/2,np2P3/2)里德伯系列的能级,是伸缩模效应比较重要. 相似文献
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在兰州重离子加速器国家实验室分别测量了H+, He2+, Ar11+和Xe20+离子轰击Ta表面过程中辐射的X射线谱, 并得到了Ta特征X射线谱中Mγ (M3N5)和Nαβ (M4,5N6,7)线的强度, 即Iγ和Iαβ. 分析结果表明, 强度比值Iγ/Iαβ 随着入射离子原子序数的增加而显著增加, 这是由于碰撞过程中Ta原子的多电离效应使M3支壳层的荧光产额ω3产生了显著增强. 相似文献
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Summary The collision-assisted electric-quadrupole transition 4s
21
S
0→4s3d
1
D
2 of calcium at 4575 ? has been observed using the laser-enhanced ionization technique for the first time. A blue satellite
band due to the interaction of calcium 4s3d
1
D
2 state with argon1
S
0 has also been detected at 4527 ? which is shifted by 48 ? from the isolated atomic calcium line. The line broadening cross-section
for the blue satellite has been calculated by measuring its collisional broadening at various argon pressures. Important processes
involved in the generation of this blue satellite band are qualitatively discussed.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
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D. Veza R. Beuc S. Milosevic G. Pichler 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,2(1):45-52
We report measurements and a theoretical explanation of the cusp-shaped satellite bands in the blue wing of the cesium D2 resonance line which have been observed for the first time. The bands are identified as transitions where the upper state dissociates into the 6 2P
3/2
+ 6
2
S
1/2
atomic asymptote. The experiment has been performed using a standard absorption setup, computer controlled data acquisition
and computer data processing. We have shown that the peculiar shape of the difference-potential curve is solely responsible for the spectrum containing the cusp-shaped satellite bands. The appearance
of these satellite bands has been discussed and explained relating the theory of satellite bands to the catastrophe theory.
The shape of the line wing and of the satellite bands have been calculated using the Fourier transform technique. To ensure
a more stringent comparison between the experimental and the theoretical spectrum, we have analyzed and compared the derivatives
of the measured and the calculated satellite band shape. On the contrary to the customary direct comparison between the measured and the calculated absorption coefficient, the derivative
clearly shows all differences and resemblances between satellite band profiles. The degree of coincidence of the experimentally
observed and the theoretically calculated satellite band shape can be used as an ultimate check on the assessment of the quality
of potential-energy curves involved in the formation of satellite bands.
Received: 1 October 1997 / Revised: 14 January 1998 / Accepted: 24 February 1998 相似文献
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X. J. Liu Y. Z. Qu B. J. Xiao J. G. Wang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(1):57-65
The dielectronic recombination (DR) of neonlike gold ions is investigated employing the flexible atomic code based on the
relativistic configuration interaction method, and its influence on the ionization balance and radiation energy in high-temperature
plasma is also studied. The total resonance strength for LMM configuration complex is in a good agreement with the experimental
measurement and other theoretical works. The DR rate coefficients are calculated and compared with the three-body recombination
and radiative recombination rate coefficients. The DR process is the dominant recombination mechanism of Ne-like gold ions
for plasma with temperature Te≥6.5 keV and density ne≤2×1022 cm-3, which is close to the condition of X-ray conversion region in the inertial confinement fusion. Moreover, the DR satellite
spectra of LMM, LMN and LMO resonances are simulated, and compared with the intensities of the corresponding resonance lines
induced by the electron impact excitation. The intensity ratio of the satellite line 3D’ [(2p53/23d3/23d5/2)J=5/2[(2p^{5}_{3/2}3d_{3/2}3d_{5/2})_{J=5/2}–(2p63d3/2) J=3/2](2p^{6}3d_{3/2})_{ J=3/2}] and the resonance line 3D [(2p53/23d5/2)J=1[(2p^{5}_{3/2}3d_{5/2})_{J=1}–(2p6)J=0](2p^{6})_{J=0}] is given, which can be applied for diagnostics of plasma temperature. 相似文献
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Nuclear magnetic resonance on oriented206BiFe and182ReFe has been measured using recoil implanted samples. Clearly resolved satellite structures were found for both systems. By annealing at an appropriate temperature, the resonance width was reduced. The satellite line structure for182ReFe was studied with various annealing temperatures. The ratio of the resonance strength changed with the annealing temperature. The resonances for182ReFe were also measured in external magnetic fields of 0.1, 0.2 and 0.4 T. The resonance frequencies for the satellite structure at an external magnetic field of 0.2 T were determined:v
1=691.7(3),v
2=684.4(2),v
3=687.2(2) MHz for206BiFe;v
1=231.15(5),v
2=230.20(5) for182ReFe. The origin of the satellite structure is discussed. The effective relaxation time of182ReFe at 8 mK and external magnetic field of 0.2 T was determined to be 18.6(6) s using a single-exponential fit. 相似文献
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在CS2介质中观测到由声波引起的布里渊增强非简并四波混频(NFWM)和由分子取向栅产生的瑞利型NFWM.研究发现,分子取向栅与声波之间并不是相互独立的,声波的存在会破坏瑞利型NFWM和布里渊增强NFWM极化之间的相位关系.
关键词:
四波混频
布里渊散射
瑞利散射 相似文献
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Ch. Chardonnet F. Guernet G. Charton Ch. J. Bordé 《Applied physics. B, Lasers and optics》1994,59(3):333-343
We present the narrowest molecular lines so far recorded in the 10 µm spectral region. A linewidth of 80 Hz (HWHM) has been obtained for theP(39)A
1
3
(–) line of OsO4, by selecting slow molecules (T
eff=0.6 K) in saturation spectroscopy at low laser fields (30 nW) and low pressures (2 × 10–6 Torr). In these conditions, the contribution of the fast molecules is greatly reduced because of the finite size of the beam. This method, applied previously to methane at 3.39 µm, is used for the first time in an external cell and improves by a factor 8 the best resolution of our spectrometer. Heterodyne detection and double frequency modulation have been necessary to extract a signal at a contrast of only 10–6. The physical ideas concerning this regime are described and a detailed analysis of the line shape is given. 相似文献
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A. V. Sidorov 《Physics of Particles and Nuclei Letters》2006,3(2):69-71
We compare the higher-twist (HT) contribution to the unpolarized structure function F
3 with its contribution to the nonsinglet combination g
1
p
-g
1
n
of the polarized proton and neutron structure functions using the assumption that the HT contributions to the Gross-Llewellyn
Smith and the Bjorken sum rules are similar. We have found that the relation
is valid for x≥0.1 and for x≥0.2 in the case of LO and NLO QCD approximations, respectively.
The text was submitted by the author in English. 相似文献
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The X-ray satellite spectra arising due to 2p
3/2
−13x
−1−3x
−13d
−1 (x ≡ s, p, d) transition array, in elements with Z = 40 to 48, have been calculated, using available Hartree-Fock-Slater (HFS) data on
1s
−1−2p
−1 3x
− and 2p
3/2
−1−3x
−1,3x
−1 Auger transition energies. The relative intensities of all the possible transitions have been estimated by considering cross
— sections for the Auger transitions simultaneous to a hole creation and then distributing statistically the total cross sections
for initial two hole states 2p
3/2
−1−3x
−1 amongst various allowed transitions from these initial states to 3x
−1 3d
−1 final states by Coster-Kronig (CK) and shake off processes. In both these processes initial single hole creation is the prime
phenomenon. Each transition has been assumed to give rise to a Gaussian line and the overall spectrum has been computed as
the sum of these Gaussian curves. The calculated spectra have been compared with the measured satellite energies in Lα1 spectra. Their intense peaks have been identified as the observed satellite lines. The peaks in the theoretical satellite
spectra were identified as the experimentally reported satellites α3, α4 and α5, which lie on the high-energy side of the Lα1 dipole line. 相似文献
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《X射线光谱测定》2005,34(3):179-182
The energies and intensities of the various transitions corresponding to the transition scheme 2p3/2?13x?1–3x?13d3/2?1 (i.e. L3Mx–MxM4) were used to compute theoretical Lα2 satellite spectra in 13 elements in the atomic number range of 62 ≤ Z ≤ 90. The energies were calculated using available HFS data on K–LM and L–MM transition energies. The intensities of all the possible transitions were estimated by considering cross‐sections for the Auger transitions simultaneous to a hole creation and then distributing statistically the total cross‐sections for initial two‐hole states 2p3/2?13x?1 (L3Mx) amongst various allowed transitions from these initial states to 3x?13d3/2?1 (MxM4) final states. Each transition was assumed to give rise to a Gaussian line and the overall spectrum was computed as the sum of these Gaussian curves. The calculated spectra were compared with the available measured Lα satellite spectra. The peaks in the theoretical satellite spectra were identified as the experimentally reported satellites Lαs, La13, La14 and La17, which lie on the high‐energy side of the Lα2 dipole line. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Dinu Iuga Arno P. M. Kentgens 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,158(1-2)
Double frequency sweeps can induce spin transitions in a set of satellites of a half-integer quadrupolar nucleus by simultaneously passing through resonance for a satellite pair. It is shown that by transferring population from the outer spin levels to the inner |1/2 and |−1/2 levels an increased intensity for central transition spectra is obtained. Although Magic Angle Spinning in principle interferes with this process, and the adiabaticity of the passages is different for every crystallite in a powder, enhanced spectra with undistorted line shapes are obtained for I=3/2 (23Na) and 5/2 (27Al) spins experiencing quadrupolar interactions with ωQ in the range 0.1–3 MHz. Even at spinning speeds up to 30 kHz significant enhancements are obtained. An analysis of the combined effects of double frequency sweeps (DFS) and MAS indeed shows strongly different effects for different crystallites in powder ranging from no gain at all to the theoretical maximum gain of 2I. As the effects are randomly distributed over all orientations on a sphere this is averaged over the whole line shape. Therefore, undistorted powder patterns are obtained enhanced by the average gain over the individual crystallites. Saturation of the satellite transitions, which can only be achieved if spin–spin relaxation is sufficiently strong, leads to identical results. Optimization of the sweeps should be toward an optimal effect on the population transfer to the central levels and chosen short with respect to spin–lattice relaxation times. 相似文献