共查询到17条相似文献,搜索用时 78 毫秒
1.
对铀原子单色和双色多光子共振电离光谱,进行了深入的研究。把亚稳态3800cm-1做为起始态,用双色三光子共振电离技术,在37900~38654cm-‘范围内获得了60个铀原子奇宇称高激发态能级的能位值和J值。 相似文献
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由亚稳态铀原子用双色三光子电离光谱测量铀原子奇宇称高激发… 总被引:2,自引:2,他引:0
对铀原子单色和双色多光子共振电离光谱,进行了深入的研究。把亚稳态3800cm^-1做为起始,用双色三光子共振电离技术,在37900~83654cm^-1范围内获得了60个铀原子奇宇称高激发态能级的能位值和J值。 相似文献
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用共振电离质谱测定铀原子奇宇称高激发态能级 总被引:1,自引:1,他引:0
对铀原子单色和双色多光子共振电离光谱开展了深入的研究。报道了用双色三步共振光电离技术测量位于33003 ̄34264cm^-1范围内的奇宇称高激发态能级的位置。利用总角动量选择定则指定了这些能级的总角动量J值。 相似文献
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此文计算了Z=18-82的原子在北京同步辐射4B9A束线的白色X光照射下的光电离积分截面G值。结果表明,有三个G值较大的区域,Z=18-20,39-47和59-82,最大值分别为3.8×10-6,1.6×10-5和3.5×10-5photons·cm2/s。同时,估计了平衡时主要多重电荷态离子数目,分析了用同步辐射和离子阱进行多重电荷态实验的新的候选原子,讨论了有关实验方法和技术。 相似文献
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两束双色激光脉冲能在大气中产生MV/cm的强太赫兹波.本文主要介绍了我们最近的三项理论和实验工作,澄清了双色激光方案的物理机制这个长期存在的问题,并对该方案进行了推广.为了在气体中有效地产生太赫兹波,在广泛研究的双色激光方案中两束激光的频率比ω_2/ω_1总是被取为1:2.首先从理论上预测采用其他频率比时,此方案仍能有效地工作,并通过实验进行证实.实验上观察到在新的频率比ω_2/ω_1=1:4,2:3下,也能有效地产生太赫兹波;观察到通过旋转较长波长的激光脉冲的偏振方向,能够有效地调节太赫兹波的偏振,但是旋转波长较短的激光脉冲的偏振方向,太赫兹波的偏振几乎没有变化,这违背了多波混频理论中极化率张量对称性的要求;采用不同的频率比时,太赫兹能量定标率并没有显示出明显的区别,这与多波混频理论预测的能量定标率不符.这些实验结果与等离子体电流模型及粒子模拟结果符合得很好.因此,该研究不仅对双色激光方案进行了推广,而且证实了其物理机制应该归结为等离子体电流模型. 相似文献
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分别计算了原子光电离跃迁过程的Hatree-Fock(HF)初态波函数、Hatree-Fock-Slater(HFS)初态波函数和HFS末态波函数,并就两种不同初态波函数,对部分元素的不同壳层的光电离跃迁库泊零点能进行了计算,最后对两种计算结果作了比较。 相似文献
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钆同位素可作为生产医用同位素161Tb等的靶材,受限于高效光电离路径缺失等问题,目前仅能通过电磁方法生产,为实现钆的多步光电离,需要获取高激发态等光谱数据.基于国内自主研发的高分辨激光共振电离质谱,利用双色三步光电离方案,扫描了钆的36900~37700 cm-1能区,首次获取了7条奇宇称高激发态能级,能级位置准确度可达±0.1 cm-1,并根据角动量选择定则确定了可能的J值,同时发现了可用于质谱性能检验的单色光电离谱线. 相似文献
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Two-colour coherent control of multiphoton ionization: a comparison between long-range and short-range potential model atoms
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Using the numerical solution of the time-dependent Schr\"odinger
equation of a one-dimensional model atom in a two-colour laser field,
we have investigated the effects of the potential models on coherent
control of atomic multiphoton ionization. It is found that the
photoelectron spectra are obviously different for the long-range
(Coulomb-like) and short-range (with no excited bound states)
potential model atoms, which are produced by two-colour coherent
control of atomic multiphoton ionization in a few laser cycles. Our
results indicate that two-colour coherent control of atomic
multiphoton ionization can be observed in simulations, depending on
the choice of the model potentials. 相似文献
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In this paper high-order harmonic generation (HHG) spectra and the ionization probabilities of various charge states of small cluster Na2 in the multiphoton regimes are calculated by using time-dependent local density approximation (TDLDA) for one-colour (1064 nm) and two-colour (1064 nm and 532 nm) ultrashort (25 fs) laser pulses. HHG spectra of Na2 have not the large extent of plateaus due to pronounced collective effects of electron dynamics. In addition, the two-colour laser field can result in the breaking of the symmetry and generation of the even order harmonic such as the second order harmonic. The results of ionization probabilities show that a two-colour laser field can increase the ionization probability of higher charge state. 相似文献
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This paper studies the multiphoton resonant ionization by two-colour laser pulses in the hydrogen atom by solving the time-dependent Schroedinger equation. By fixing the parameters of fundamental laser field and scanning the frequency of second laser field, it finds that the ionization probability shows several resonance peaks and is also much larger than the linear superposition of probabilities by applying two lasers separately. The enhancement of the ionization happens when the system is resonantly pumped to the excited states by absorbing two or more colour photons non-sequentially. 相似文献
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Th. Billen K. Schneider T. Kirsten A. Mangini A. Eisenhauer 《Applied physics. B, Lasers and optics》1993,57(2):109-112
Here we describe experiments aimed at developing an element-selective ion source for thorium (Th). The technique applied is resonance ionization spectroscopy (RIS) with a thermal atom beam. Ionization schemes for isotopically nonselective ionization of Th as well as for isotopically selective ionization of 230Th are proposed. The RIS-scheme used is two-photon two-colour ionization with excitation in the ultraviolet spectral range between 244 nm and 267 nm or in the visible spectral range between 485 nm and 529 nm. Ionization of the excited atoms is performed either by ultraviolet photons or by visible photons, depending on the energy required for this process. 相似文献
15.
M. Fifirig A. Cionga F. Ehlotzky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):333-336
The two-photon ionization of the hydrogen atom from its ground state by a two-colour electromagnetic field consisting of two
odd harmonics of the same IR laser is analyzed. The influence of the state of polarization of the bichromatic field on the
azimuthal angular distribution and the dependence of the elliptic dichroism on the photon frequencies are reported.
Received 11 December 2002 Published online 29 April 2003
RID="a"
ID="a"e-mail: fritz.ehlotzky@uibk.ac.at 相似文献
16.
boldmath Broadband water window supercontinuum generation with a ω+3ω/2 multicycle two-colour pulse
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We propose a method to generate a high-efficiency broadband water window supercontinuum with a ω+3ω/2 multicycle two-colour pulse. Our results reveal that the 3ω/2 laser pulse can simultaneously modulate the acceleration step and the ionization step, which not only broadens the bandwidth but also enhances the yield of the generated supercontinuum. An ultra-broadband supercontinuum from 290 eV to 555 eV covering the whole water window is generated. Using this method, we expect that an isolated 62-as pulse with a minor pre-pulse can be directly obtained. 相似文献
17.
A comprehensive set of spectra for the benzene cation and the perdeuterated benzene cation has been recorded with full rotational resolution using zero kinetic energy photoelectron spectroscopy (ZEKE) at high resolution (up to 0.2 cm?1), using a slow-rising extraction pulse. With different rovibronic levels in the S1 6l state as intermediate resonance, the rotational transitions to the vibronic ground state of the cation have been recorded using two-colour, two-photon resonance enhanced multiphoton ionization. A simple spectator model has been employed to simulate the intensities of the ZEKE transitions. By fitting the simulations to the recorded spectra, improved values for the rotational constants and the Coriolis coupling parameters of benzene and perdeuterated benzene have been obtained. The CC and CH bond lengths of the cation have been deduced. The spectator model is shown to be reliable despite the fact that no specific allowance is made for the effect of final state interactions on the signal intensity. 相似文献