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测量了GdVO4 ∶Eu3 +在室温下的光致发光光谱 ;研究了不同掺杂方式和烧结气氛对多晶GdVO4 ∶Eu3 +发光性质的影响 ,探讨了GdVO4 ∶Eu3+的激发光谱在 2 0 0~ 35 0nm范围内激发带的来源和GdVO4 ∶Eu3+中的能量传递。在 2 0 0~ 35 0nm范围内的激发带可解释为来自于钒酸根团的配体O到V的电荷迁移跃迁吸收 ;硝酸溶液使部分正GdVO4 形成多钒酸盐 ,还原气氛使GdVO4 产生O空位和部分V变价 ,影响了钒酸根团间的电荷迁移跃迁吸收和钒酸根团间、钒酸根团与Eu3 +间的能量传递 ,产生激发谱带蓝移和激发带间强度比例变化。GdVO4 中VO3 -4 的π轨道能使得VO3 -4 和稀土离子 (Gd3+、Eu3+)的电子波函数有效地重叠 ,从而VO3 -4 和稀土离子可通过交换作用有效地传递能量。GdVO4 ∶Eu3+在 2 0 0nm处的吸收很弱 ,在此位置也没有Gd3 +或Eu3+的 4fn -15d的吸收和明显的 4fn 高能级吸收 ,而激发却十分有效 ,可解释为由于存在VO3 -4 与Gd3 +或Eu3+的 4fn 高能级间有效的能量传递所致 ;由于Gd3 +的特征发射恰好在基质的强激发带 ,且Gd3+的特征发射没有出现 ,可存在Gd3 +→VO3-4 →Eu3 +的能量传递。Gd3+的6GJ、6PJ能级间隔与Eu3 +的7F1、5D0 能级间隔相近 ,处于6GJ态的Gd3 +可通过共振能量传递激发Eu3 +到5D0 态 ,这可导致Gd3 + 相似文献
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测量了GdVO4:Eu^3 在室温下的光致发光光谱;研究了不同掺杂方式和烧结气氛对多晶GdVO4:Eu^3 发光性质的影响,探讨了GdVO4:Eu^3 的激发光谱在200~350nm范围内激发带的来源和GdVO4:Eu^3 中的能量传递。在200~350nm范围内的激发带可解释为来自于钒酸根团的配体O到V的电荷迁移跃迁吸收;硝酸溶液使部分正GdVO4形成多钒酸盐,还原气氛使GdVO4产生O空位和部分V变价,影响了钒酸根团间的电荷迁移跃迁吸收和钒酸根团间、钒酸根团与Eu^3 间的能量传递。产生激发谱带蓝移和激发带间强度比例变化。GdVO4中VO4^3-的π轨道能使得VO4^3-和稀土离子(Gd^3 、Eu^3 )的电子波函数有效地重叠,从而VO4^3-和稀土离子可通过交换作用有效地传递能量。GdVO4:Eu^3 在200nm处的吸收很弱,在此位置也没有Gd^3 或Eu^3 的4f^n-1 5d的吸收和明显的4f^n高能级吸收,而激发却十分有效,可解释为由于存在VC4^3-与Gd^3 或Eu^3 的4f^n高能级间有效的能量传递所致;由于Gd^3 的特征发射恰好在基质的强激发带。且Gd^3 的特征发射没有出现,可存在Gd^3 →VO4^3-→Eu^3 的能量传递。Gd^3 和^6GJ、^6PJ能级间隔与Eu^3 的^7Fl、^5D0能级间隔相近,处于^6GJ态的Gd^3 可通过共振能量传递激发:Eu^3 到^5Dn态,这可导致Gd^3 →Eu^3 离子的能量传递。 相似文献
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实验测定了CaO-Al2O3二元系中晶体和玻璃的拉曼光谱,并利用密度泛函理论(DFT)计算了CaAl4O7晶体的拉曼光谱活性振动波数和散射活性。结果表明CaAl4O7的中波数区(400~700 cm-1)对应Al-Ob-Al的弯曲振动,高波数区(700~1 000 cm-1)则对应Al-Onb的伸缩振动。采用激光悬浮加热装置制备了一系列玻璃样品,对其进行拉曼光谱研究发现,550和780 cm-1附近观察到两个明显的特征峰,分别对应Al-Ob-Al的弯曲振动和Al-Onb的伸缩振动。随着CaO/Al2O3比例的增加,550 cm-1特征峰发生蓝移,而780 cm-1特征峰发生红移,表明复杂网络结构逐渐解聚。此外,随Al<... 相似文献
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Method for fitting crystal field parameters and the energy level fitting for Yb3+ in crystal Sc2O3 下载免费PDF全文
<正>A method to compute the numerical derivative of eigenvalues of parameterized crystal field Hamiltonian matrix is given,based on the numerical derivatives the general iteration methods such as Levenberg-Marquardt,Newton method, and so on,can be used to solve crystal field parameters by fitting to experimental energy levels.With the numerical eigenvalue derivative,a detailed iteration algorithm to compute crystal field parameters by fitting experimental energy levels has also been described.This method is used to compute the crystal parameters of Yb~(3+) in Sc_2O_3 crystal, which is prepared by a co-precipitation method and whose structure was refined by Rietveld method.By fitting on the parameters of a simple overlap model of crystal field,the results show that the new method can fit the crystal field energy splitting with fast convergence and good stability. 相似文献
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Diode-Pumped Quasi-Three-Level Passively Q-Switched Nd:GGG Laser with a Codoped Nd,Cr:YAG Saturable Absorber 下载免费PDF全文
We demonstrate the first quasi-three-level passively Q-switched Nd:GGG laser at 937nm using a Nd, Cr:YAG crystal as the saturable absorber. The dependences of the average output power, the repetition rate and the pulse width on the incident pump power are obtained. A maximum average output power of 1.18 W with repetition rate of 35kHz and pulse width of 45ns is achieved at an incident pump power of 18.3 W. The corresponding optical-to-optical and slope efficiencies are 6% and 10%, respectively. 相似文献
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In this paper, Cr-doped LiSrAlF6 crystals are investigated using high-temperature Raman spectroscopy and the single-crystal Raman spectra of Cr:LiSrAlF6 are analysed by factor group theory and comparison with other fluorides. The results indicate that Cr:LiSrAlF6 is stable below its melting point; Raman peaks located at 561, 322 and 250 cm-1 are assigned to the A1g modes of AlF6, SrF6 and LiF6 octachdra, respectively; with temperature increasing, Raman peaks associated with AlF6 octahedra shift towards low frequencies, while LiF6 and SrF6 octahedra are temperature-insensitive; around the crystal melting point, three new Raman peaks occur, which are associated with the AlF6 octahedral chain structure. Finally, the microstructural evolution of Cr:LiSrAlF6 from room temperature to its melting point is discussed based on its Raman spectra. 相似文献