共查询到20条相似文献,搜索用时 15 毫秒
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W.R. Dixon T.J.M. Symons A.A. Pilt K.W. Allen C.H. Zimmerman F. Watt S.P. Dolan 《Physics letters. A》1977,62(7):479-482
The mean lifetime of the 3907 keV state of 19F has been measured by the Doppler shift attenuation method (DSAM). The value obtained was 9 ± 5 fs. Transition strengths derived from this lifetime and previously measured branching ratios are compared with the results obtained from shell model calculations. The importance of including particle-hole configurations is discussed and it is shown for example that the energy and lifetime of the state are consistent with a predominantly p?2 sd5 structure. 相似文献
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The lifetime of the 5.14 MeV excited state of 22Ne was investigated by use of the electronic timing, recoil distance and Doppler shift attenuation techniques. A mean life τ = 1.2±0.3 ps was obtained, corresponding to a transition strenght of 9.8 × 10?6W.u. for the El decay of this state. 相似文献
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Judith A. Halstead Robert R. Reeves 《Journal of Quantitative Spectroscopy & Radiative Transfer》1982,28(4):289-296
A pulsed tunable dye laser was used for a high resolution experimental study of mercury fluorescence from the 63P1 state. The output of the dye laser was frequency doubled into the 253.7 nm region using a potassium penta-borate crystal. Exponential decays were observed for each of the five individual components of the hyperfine structure separately and the effects of the trapping of resonance radiation on the observed lifetime of the 63P1 state of mercury were investigated for each resolvable component. Within experimental error, the natural radiative lifetime of the 63P1 state was found to be independent of the hyperfine component irradiated and a value of 122±2 nsec was obtained, consistent with results found by other methods. 相似文献
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在2—300K温度范围,研究了纯的及掺Mg2+,Ni2+和Co2+的准一维反铁磁体CsMnCl3·2D2O(CMC)中Mn2+离子的4T1激子的能量转移动力学过程,发现在2—10K范围,激子的荧光强度和寿命随温度很快下降,较高浓度的杂质离子将进一步加快荧光的减弱和寿命的缩短。这种现象被归结为与磁相互作用和自旋有序相关联的多声子无辐射跃迁及施主—受主之间的能量转移。在更高的温度,能量转移速率增高,但由于仍然存在的自旋短程有序和Jahn-Teller效应,施主之间的能量迁移受到一定限制,出现非指数衰减过程。各种不同的杂质离子在某种程度上显示出不同的陷落作用和弛豫特性。
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A.J. Rutten A. Holthuizen W.A. Sterrenburg C.P.M. Van Engelen G. Van Middelkoop 《Nuclear Physics A》1981,359(2):442-454
The g-factor and mean life of the state at 3.85 MeV in 13C have been determined by a recoil-into-vacuum plunger measurement. The state was populated by the 2H(12C, p) reaction at E = 15.0 MeV. The analysis of the time-differential deorientation effect on the p-γ angular correlation leads to a g-factor of . For the mean lifetime a value of τ = 12.2 ± 0.4ps is obtained. 相似文献
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Hanle-effect studies were made of 13 identified lines belonging to the 5933-, 6117-, 6125-, and 6126-Å bands of the NO22B2 state. The fluorescence was excited using a tunable cw dye laser operated single mode, using NO2 pressures as low as 0.2 mTorr. From the variation of the fluorescence intensity with magnetic field the product gτC is deduced, where g and τC are the excited state g value and coherence lifetime, respectively. Using previously determined radiative lifetimes, g is obtained and compared to the values of g expected from Hund's case (b) coupling. The observed g values do not display the expected N′ dependence and are about an order of magnitude smaller than predicted. An alternative explanation is that the g values are behaved, but the coherence lifetime is shorter than the radiative lifetime, caused by radiationless dephasing processes which may be collisional or intrinsic. 相似文献
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The mean lifetime of the 0.78 MeV first excited state in 209Pb was measured by the recoil distance method to be τm = 11.1±1.3 ps. The B(M1) for the l-forbidden transition is in good agreement with one of several recent theoretical predictions. 相似文献
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OH-对磷酸盐铒玻璃光谱性质的影响 总被引:11,自引:0,他引:11
本文系统研究了Yb3+、Er3+共掺磷酸盐铒玻璃中OH-含量与铒玻璃荧光寿命和光谱性质的关系.结果表明OH-基团的存在使得Er3+离子的荧光强度显著降低,荧光寿命大大缩短.比较了三种不同Al2O3含量(5mol%,8mol%和13mol%)的铒玻璃在2.9μm波长处的红外吸收系数与铒离子荧光寿命的关系,发现玻璃中OH-在2.9μm的吸收系数和Er3+的4Ⅰ13/2能级离子衰减速率成线性关系,不同Al2O3含量的玻璃具有不同Er3+和OH-基团的相互作用参量和不同的荧光寿命值及量子效率.并从玻璃结构上解释了Al2O3含量对除水机制和光谱性质的影响.经过充分除水后的铒玻璃荧光寿命可达到9.1ms. 相似文献
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使用波长为808和658nm的半导体激光器和染料激光器作为激发源,测量了Er3+:YVO4晶体的波长在553和410nm附近的上转换荧光.对激发过程的分析表明,贡献于上转换荧光的主要激发机制为激发态吸收.在不同浓度下对上转换荧光的寿命测量结果显示,随Er3+浓度的提高,553nm绿光的荧光寿命随浓度的增加而减小,但410nm的荧光寿命随Er3+浓度无明显变化.结合绿光强度随掺杂浓度增加而减小的结果,认为在所测浓度范围内
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本文讨论二价铁对铁氧体的铁磁共振线宽的影响。由于在尖晶石型铁氧体中,二价铁的基态是轨道单态,晶场的直接效应很小。二价铁对铁磁共振性质有显著影响的原因是各向异性交换作用引起二价铁磁矩不与总磁矩平行,因而使得文献[1]中所述的纵分支对共振性质起作用。我们推广文献[1]中的方法,使之适用于强交换耦合体系,并用之计算了二价铁对共振线宽的影响。计算表明,体系间的交换耦合的强弱对线宽的影响很小。对含二价铁反型尖晶石型铁氧体算得的结果解释了[100]方向线宽随温度的变化不出现极大,而在其他方向则出现极大的现象。导出的线宽的各向异性也与实验相符。 相似文献
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The branching ratio of the following three modes of K+-meaon decay K+→μ++π0+ν K+→e++π0+ν K+→μ++ν is calculated by using the theory of the universal Fermi weak interaction proposed by Feymann and others. Perturbation method with cut-off is used. The ratio obtained is 1:1.5:12, which is in fair agreement with the experimental value 1:1:15. It is shown, other conbinations of Fermi interactions can not give result in agreement with experiment. 相似文献
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K.A. Mohamed G.C. King F.H. Read 《Journal of Electron Spectroscopy and Related Phenomena》1977,12(3):229-237
The lifetime of the (B3Σ+υ= 0, 1 state of the CN radical has been measured by the photon-photon delayed coincidence technique, the CN radical being produced by electron impact dissociation of acetonitrile. This is the first lifetime measurement in a free radical by this method. The optical cascade in the band spectrum of CN used for the present measurement is H2Πr - B2Σ+ - X2Σ+. The lifetime of the (B2Σ+)υ=0, 1 state in CN has been found to be 61.1 ± 7.6 ns. 相似文献