共查询到20条相似文献,搜索用时 109 毫秒
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在钠原子-分子混合体系中,实验研究了加入缓冲气体对高位态原子-分子碰撞能量转移和分子扩散带辐射的增强效应;运用瞬态碰撞模型作了理论计算,理论结果与实验结果相符合。 相似文献
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利用双光子吸收,将Na(3S)原子激发到4D态,测量了Na(4D)+Na(3S)Na(4F)+Na(3S)碰撞能量转移截面,因为直接由4F→3D的荧光不能探测,所以检测3D→3P级联荧光讯号。结合基态钠原子密度的测量,给出了截面值σ_4D→4F=1.3 x 10~(-14)±28%(cm~2)。 相似文献
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一、引 言 这里的非共振发射谱是来源于碰撞引起的激发态精细结构之间的能量转移.对Na的第一激发态就是 Na(32P3/2)+X Na(32P1/2)+X+ E(1)其中X是具有一定动能的碰撞原子,△E是3P态精细结构分裂能量。 精细结构之间的能量转移过程的研究不仅对于了解原子之间相互作用的机制有重要作用,而且很有实际意义.例如,最近Gelhwachs等人[1]把饱和光学非共振发射谱用于Na的单原子检测得到了相当好的结果. 我们利用Ar+激光泵浦的连续染料激光器对Na原子的D1,D2线分别进行选择性激发.观察了共振及非共振荧光.研究了它们随激发光强、Na原子密… 相似文献
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对钠蒸气中的碰撞能量合并过程Na(3PJ)+Na(3PJ′)→Na(nLJ″)+Na(3S1/2)进行了实验研究.在低钠原子密度条件下,用激光将原子分别激发到3P1/2或3P3/2态,测量从nLJ″态发出的荧光强度比和Na(3P3/2)与Na(3P1/2)的密度比,给出了J′=J=1/2或3/2,nLJ″=4D3/2,4D5/2,4F5/2,4F7/2,5S1/2的速率系数对打的比值、当销原子密度足够高时,3P态以统计比率布居,得到了k(nLJ″)(1/2,3/2)对k5S(3/2,3/2)的比值.
关键词: 相似文献
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S. Gozzini A. Lucchesini L. Marmugi G. Postorino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(1):1-5
Sodium photoejection from a paraffin coated cell has been
observed and analyzed in detail. The effect has been detected by observing the fluorescence induced by a cw dye laser. A maximum
Na density of about 2.9 ×108 atoms/cm3 was obtained by shining the cell with 1.05 W Ar+ laser green light. A progressive slowing of the dynamics of the process is reported, probably due to a change in the chemical
rearrangement of the Na atoms in the coating under intense light exposure. This aging effect represents a limitation in the
practical application of this kind of materials. 相似文献
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Tb3+和Na2WO4共掺杂SiO2材料的制备及其发光性质 总被引:2,自引:0,他引:2
通过溶胶-凝胶技术制备了稀土离子Tb3 和Na2WO4共掺杂的SiO2材料,利用DTA-TG,IR,XRD等测试手段研究了材料的结构。材料属于非晶态,800℃退火后Tb3 和Na2WO4共掺杂样品的主要结构为SiO2的网状结构。通过三维荧光光谱,荧光激发光谱和发射光谱,分析探讨了Na2WO4对掺稀土离子的SiO2体系发光性质的影响。结果显示,在230nm激发下,样品显示Tb3 的5D4—7Fj(j=4,5,6)和5D3—7Fj(j=4,5,6)发射光谱,在紫外灯的照射下,发射均匀的蓝绿色荧光,说明样品掺杂均匀且分散性较好。Na2WO4的掺入,并不影响Tb3 在SiO2基质中的发射峰的主要位置,但对发光强度有很大的影响,敏化了5D4—7F6蓝色跃迁而猝灭了5D4—7F5绿色跃迁,使材料发射蓝绿色荧光。文章通过所得的能级图,对样品的跃迁机理进行了分析。 相似文献
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I. V. Stanishevsky S. M. Arabei V. A. Chernyavskii K. N. Solovyev 《Optics and Spectroscopy》2016,121(5):722-728
For a number of porphyrin molecules, it was shown that their excitation by light pulses of a rectangular step shape and a certain duration led to experimentally observed dynamical decrease and increase of fluorescence kinetics due to changes in the population of the lower (metastable) triplet T1 state. On the basis of exact analytical expressions for a three-energy-level model, a simple analytical relationships between the rate constants of intramolecular processes and experimentally measured parameters of the fluorescence kinetics were obtained. The three-dimensional isotropic orientation of the molecules in the framework of the chosen model was taken into account by numerical methods and allowed to simulate adequately the experimentally observed fluorescence kinetics. The T1 state lifetimes of the studied porphyrin molecules in polymer matrices were determined from experimental curves using numerical methods for solving inverse problems. The obtained values correlated with literature data. Features and advantages of this approach were discussed. 相似文献
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J.H. Choi C.B. Stipe C.P. Koshland D. Lucas 《Applied physics. B, Lasers and optics》2006,84(3):385-388
We report in situ, real-time detection of soot particles coated with NaCl using excimer laser fragmentation fluorescence spectroscopy (ELFFS). Carbon atom fluorescence at 248 nm and the Na D-line at 589 nm are used as signatures of soot and NaCl, respectively. Soot particles are encapsulated with a NaCl layer in a well-controlled inverted flame burner. NaCl particles are injected into the methane-air co-flow flame to coat the soot particles. ArF laser irradiation of the coated particles in an air stream at 1.14 J/cm2 produces fluorescence from Na, C, and CH. At 0.69 J/cm2, which is slightly above the fluorescence threshold, but not enough for considerable fragmentation of the particles, Na D-line persists with little carbon and no CH observed. These results suggest that the photolytic fragmentation-fluorescence using 193 nm excitation can be effectively used for in situ, real-time chemical analysis of core-shell nanoparticles. PACS 78.67.Bf; 78.70.-g; 42.68.Jg 相似文献
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Codoping Na+ to modulate the spectroscopy and photoluminescence properties of Yb3+ in CaF2 laser crystal 总被引:1,自引:0,他引:1
Three kinds of Yb3+ - and Na+-codoped CaF2 laser crystal with different Na:Yb ratios of 0, 1.5, and 10 are grown by the temperature gradient technique. Room-temperature absorption, photoluminescence spectra, and fluorescence lifetimes belonging to the transitions between ground state 2F7/2 and excited state 2F5/2 of Yb3+ ions in the three crystals are measured to study the effect of Na+. Experimental results show that codoping Na+ ions in different Na:Yb ratios can modulate the spectroscopy and photoluminescence properties of Yb3+ ions in a CaF2 lattice in a large scope. 相似文献
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研究了荧光素(Fluorescein)与阴离子表面活性剂(Anioni surfactant)十二烷基苯磺酸钠(Sodiun dodecyl benzenesulfonate)、十二烷基磺酸钠(Sodium laurylsulfonate)、十二烷基硫酸钠(Sodiumdodecyl sulphate)的荧光性质,探讨了实验条件对荧光素与阴离子表面活性剂荧光性质的影响。研究结果表明,在室温下,pH 7.3-7.7 Na2HPO4-KH2PO4缓冲溶液中,体系中加入十二烷基苯磺酸钠、十二烷基磺酸钠后荧光强度增强,加入十二烷基硫酸钠后荧光强度减弱。建立了荧光光度法测定十二烷基苯磺酸钠的新方法。 相似文献
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介绍了多碱光电阴极Na2KSb膜层荧光谱的测量原理,测量了两个Na2KSb膜层样品在不同半径位置的荧光谱.测量数据表明,Na2KSb膜层荧光谱的峰值波长从阴极面的中心到边缘逐步增大,同时峰值荧光强度也逐步增强.原因是阴极窗表面的锑原子密度从中心向边缘逐步减小.当Na2KSb膜层中的锑超过Na2KSb所需的化学计量比时,荧光峰值波长向短波方向移动,同时荧光强度减弱;当Na2KSb膜层中的锑达到Na2KSb所需的化学计量比时,荧光峰值波长达到最大,同时荧光强度也达到最强.通过荧光测试,可以判断Na2KSb膜层的化学计量比是否达到2∶1∶1或膜层中的锑是否过量.同时通过测量阴极面上不同位置的荧光谱,可以测量Na2KSb膜层在阴极面上的组份均匀性.锑在阴极面上的原子密度越均匀,利用整个阴极面上的光电流变化来监控阴极膜层生长的方法就更准确,组份均匀性也更好,Na2KSb膜层的厚度可以更厚,对长波可见光的吸收更多,阴极的灵敏度也更高.因此在像增强器多碱阴极的制造过程中,要尽量使蒸发在阴极窗表面的锑原子密度均匀,这样才能获得更高的阴极灵敏度. 相似文献