共查询到20条相似文献,搜索用时 125 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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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.
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在高对比度透射光谱中观察到线宽18mG(FWHM)钠原子基态中碰撞增强的Hanle共振.此共振的线宽仍表现出Dicke变窄效应,但信号的强度却随着缓冲气体压强急剧地增加. 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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置于同一池中的Na原子和K原子,分别被连续染料激光器和K光谱灯激发型Na(3P),K(4P),Na(3P)原子密度由吸收等效宽度技术测定。利用调制技术,分离出了由异核碰撞产生的荧光光谱,观察到了Na(3P)和K(4P)间的磁能量合并现象,并测定了其碰撞截面。 相似文献