掺钕磷酸盐激光玻璃的光谱特性

掺钕激光玻璃广泛应用于核聚变、高功率激光放大器和光纤激光器等领域。磷酸盐玻璃热膨胀系数高、热稳定性和化学稳定性差、热机械强度低。通过改变玻璃组分,即添加Al2O3和F2,并改进制备工艺来降低热膨胀系数,除去铂和分子水。测量了磷酸盐玻璃中Nd3+离子的荧光光谱、吸收光谱及玻璃的热膨胀系数。根据吸收光谱计算掺钕磷酸盐激光玻璃的光谱参数。通过对掺钕磷酸盐玻璃的热膨胀系数的实际测量和计算,分析了玻璃的热稳定性。结果表明,在基质玻璃中引入Al2O3使激光玻璃的热膨胀系数可降低到α=38.75×10-7/℃,引入F2既达到了除水的目的又降低了玻璃的声子能量,提高了荧光发射的量子效率,并优化了光谱性能,拓展了掺钕磷酸盐激光玻璃的应用范围。     

碱土金属离子对掺铒磷酸盐玻璃除水性质的影响

以掺铒磷酸盐玻璃中铒离子寿命随OH含量变化为依据,系统研究了碱土金属离子类型和含量对磷酸盐铒玻璃除水性质的影响。结果表明,采用通干燥O2和CCl4除水工艺可有效降低玻璃中OH含量,除水效果在通气的最初阶段最为明显,玻璃中OH含量降低速率随通气时间延长而减慢,最终趋于动态平衡。值得指出的是,在相同通气时间,磷酸盐铒玻璃的荧光寿命随碱土金属离子半径增大而减短。含有较高浓度碱土金属离子的磷酸盐铒玻璃具有较短的荧光寿命,并且在停止通气后熔体重新吸水的能力变大。     

钕离子掺杂和钕铝共掺高硅氧玻璃的光谱性质研究

基于多孔玻璃烧结的方法制备了钕离子掺杂和钕铝共掺高硅氧玻璃，测量了掺钕高硅氧玻璃的吸收光谱、荧光光谱和荧光寿命. 利用Judd-Ofelt理论计算得到了钕离子在高硅氧玻璃中的强度参数，计算并对比了掺钕高硅氧玻璃和钕铝共掺高硅氧玻璃的理论荧光寿命、受激发射截面和发光量子效率.讨论了钕铝共掺高硅氧玻璃中铝离子的掺入对玻璃发光性质的影响. 通过与其他掺钕氧化物玻璃和一些商用硅酸盐玻璃的主要光谱性质的比较，掺钕高硅氧玻璃显示了较好的光谱性质，有可能成为一种应用于高能和高频激光领域的新型激光材料. 关键词： 掺钕高硅氧玻璃 钕铝共掺 光谱性质 Judd-Ofelt理论     

掺钕TeO_2-Al_2O_3-Cs_2O玻璃的Judd-Ofelt理论分析与光谱特性

采用高温熔融法制备了组分为80TeO2-10Al2O3-10Cs2O-xNd2O3(x=0,0.5,1.0)(mol%)的掺钕碲酸盐玻璃,测试了玻璃样品的折射率、吸收光谱、荧光光谱和荧光寿命曲线.利用Judd-Ofelt理论计算得到光谱强度参数Ωλ(λ=2,4,6),Nd3+从4F3/2能级到4IJ(J=9/2、11/2、13/2、15/2)能级跃迁的荧光有效线宽Δλeff,4F3/2能级跃迁几率AJ,荧光分支比β,相应的荧光寿命τrad和量子效率η及受激发射截面σemi.在该碲酸盐体系中,Nd3+离子掺杂浓度为0.5mol%时,样品在1 060nm波长处的σemi·τmeas为6.21×10-24cm2·s,荧光有效线宽为31.4nm,量子效率达到89%.光谱特性对比分析结果表明,该掺钕碲酸盐玻璃是一种性能优良的固体激光材料.     

OH~-对磷酸盐铒玻璃光谱性质的影响

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 Al2 O3 含量 ( 5mol% ,8mol%和 1 3 mol% )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4 I13 / 2 能级离子衰减速率成线性关系 ,不同 Al2 O3 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 Al2 O3 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 9.1 ms     

Yb~(3+)掺杂磷酸盐玻璃光纤与1.06μm单频激光器的研制

超短线性腔是实现单频激光稳定输出的最简单的结构,针对石英玻璃光纤掺杂离子浓度低、输出功率小的缺点,选择对稀土离子具有较高溶解度的磷酸盐玻璃作为增益介质,研究了Yb3+掺杂磷酸盐玻璃(P2O5-B2O3-K2O-BaO-Al2O3-Nb2O5-Sb2O3)的光谱特性,解决了Yb2O3高浓度掺杂和提高Yb3+荧光寿命的问题。实验表明磷酸盐玻璃对Yb2O3溶解度摩尔分数可达6%(质量分数为15.5%);通过除水技术,Yb3+离子2F5/2能级的寿命达到1.84 ms。在此基础上采用管棒法拉制出了磷酸盐玻璃单模光纤,通过光栅选频,利用1.4 cm光纤实现了中心波长1063.5 nm,功率51.6 mW的单频激光输出。     

高效氟磷酸盐玻璃白光荧光体制备及发光特性

采用熔融淬火方法制备了一系列Sn2+，Dy3+单掺及Sn2+-Dy3+共掺氟磷酸盐玻璃荧光体。利用紫外-可见分光光度计分别对各玻璃荧光体的透过光谱、激发光谱、发射光谱及荧光寿命等进行了测试和分析。结果发现在紫外光激发下，对于Sn2+、Dy3+单掺氟磷酸盐玻璃可分别获得高效的蓝光与黄光发射，且Sn2+单掺氟磷酸盐玻璃荧光体发光显色指数和量子效率最高；对于Sn2+-Dy3+共掺氟磷酸盐玻璃荧光体可实现高效的白光发射，且发现在Sn2+和Dy3+之间存在明显的能量传递，通过调节Dy3+掺杂浓度，两离子之间的能量转移效率亦随之改变，从而可对其白光色度进行调节。当Dy3+掺杂浓度为3 Wt%时，利用280 nm商用LED芯片激发可获得对应色坐标为(0.311，0.330)，量子效率为56.3%，亮度为6 706 cd·m-2的近纯白光发射。此外，对各类玻璃样品的DSC、导热及其他光学性能也进行了测试与计算，获得了各样品的热导率、量子效率、色坐标、显色指数等参数。研究结果表明，制备的高效氟磷酸盐玻璃完全有望作为可调谐白光发光荧光体应用于商用LED。     

荧光捕获效应对Yb3+磷酸盐玻璃光谱性质的影响

测试了不同掺杂浓度和不同厚度下Yb³⁺磷酸盐玻璃的吸收光谱、荧光光谱和荧 光寿命，计算了积分吸收截面、吸收截面、受激发射截面、自发辐射寿命以及荧光有效线宽等光谱参数，讨论了荧光俘获效应对Yb³⁺磷酸盐玻璃光谱性质的影响.结果表明荧光俘 获效应随样品厚度和掺杂浓度的增加而增大.由于荧光俘获效应的存在使得测量的Yb^{3+磷酸盐玻璃荧光寿命明显长于计算的荧光寿命，在0.2mol%Yb₂O₃低掺 杂浓度下 关键词： 荧光俘获 掺镱磷酸盐玻璃 荧光光谱}     

荧光捕获效应对Yb3+磷酸盐玻璃光谱性质的影响

测试了不同掺杂浓度和不同厚度下Yb3+ 磷酸盐玻璃的吸收光谱、荧光光谱和荧光寿命 ,计算了积分吸收截面、吸收截面、受激发射截面、自发辐射寿命以及荧光有效线宽等光谱参数 ,讨论了荧光俘获效应对Yb3+ 磷酸盐玻璃光谱性质的影响 .结果表明荧光俘获效应随样品厚度和掺杂浓度的增加而增大 .由于荧光俘获效应的存在使得测量的Yb3+ 磷酸盐玻璃荧光寿命明显长于计算的荧光寿命 ,在 0 2mol%Yb2 O3低掺杂浓度下采用不同厚度 ( <4mm)的样品测量的荧光寿命之间误差为 3 0 %左右 ,高浓度 ( 6mol%Yb2 O3)掺杂下误差可达 43 % .荧光俘获还造成荧光谱线加宽 ,导致荧光有效线宽在低浓度 ( 0 2mol%Yb2 O3)时增加 14% ,在高掺杂浓度 ( 6mol%Yb2 O3)下增加 3 0 %以上     

OH-对磷酸盐铒玻璃光谱性质的影响

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⁴Ⅰ_13/2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.     

The B 2Σ+–X 2Σ+ Transition of 12C17O+: The 2‐υ″ Progression

Abstract

Three new bands of the B ²Σ⁺–X ²Σ⁺ system of ¹²C¹⁷O⁺ have been investigated using conventional spectroscopic techniques. The spectra were observed in a graphite hollow‐cathode lamp by discharging molecular oxygen (enriched in about 45% of the ¹⁷O₂ isotope) under 1.0 Torr pressure. The rotational analysis of the 2–4, 2–5, and 2–6 bands was performed with the effective Hamiltonian of Brown (Brown et al., J. Mol. Spectrosc. 1979; 74: 294–318). Molecular constants were derived from a merge calculation, including both the current wavenumbers and the spectroscopic data published by the authors previously. The principal equilibrium constants for the ground state of ¹²C¹⁷O⁺ are ω_e=2185.9658(84), ω_e x _e = 14.7674(11), B _e=1.927001(38), α_e=1.8236(22)×10^?2, γ_e=?0.331(28)×10^?4, D _e=6.041(12)×10^?6, β_e=0.100(31)×10^?7 cm^?1, and the equilibrium constants for the excited state are σ_e=45876.499(15), ω_e=1712.201(12), ω_e x _e=27.3528(39), B _e=1.754109(35), α_e=2.8706(57)×10^?2, γ_e = ?1.15(19)×10^?4, D _e=7.491(20)×10^?6, β_e=2.13(12)×10^?7, γ_e = 2.0953(97)×10^?2, and α_γe=?9.46(59)×10^?4 cm^?1, respectively. Rydberg–Klein–Rees potential energy curves were constructed for the B ²Σ⁺ and X ²Σ⁺ states of this molecule, and Franck–Condon factors were calculated for the vibrational bands of the B–X system.     

Rotational Analysis of the 1–4 Band of the B 2Σ+–X 2Σ+ System of 14C16O+

ABSTRACT

High-resolution emission spectrum of the 1–4 band of the B ²Σ⁺–X ²Σ⁺ transition of ¹⁴C¹⁶O⁺ was observed for the first time by conventional emission spectroscopy. The band spectrum was excited in a water-cooled Geissler lamp filled with commercial gaseous carbon monoxide enriched in about 80% of the radiocarbon ¹⁴C. A rotational analysis has been carried out and obtained molecular constants have been merged with previously published data for the B ²Σ⁺–A ²Π_i and A ²Π_i–X ²Σ⁺ transitions. The principal equilibrium constants for the ground X ²Σ⁺ state obtained from this work are ω_e = 2121.7726(98), ω_e x _e = 13.9055(27), B _e = 1.815290(30), α_e = 1.6594(33) × 10^?2, and γ_e = ? 0.377(73) × 10^?4 cm^?1. Also, presently known experimental equilibrium molecular constants of the X ²Σ⁺ states of the CO⁺ isotopic molecules are summarized and isotopic dependence of the B _e and ω _e constants is discussed.     

The X2Π and A2Σ+ states of FH+, ClH+ and BrH+: theoretical study of their g -factors and fine/hyperfine structures

Theoretical calculations on the fine, hyperfine and Zeeman (g-factor) parameters are reported for the X²Π and A²Σ⁺ states of FH⁺, ClH⁺ and BrH⁺. The fine-structure constants [spin–orbit (A), Λ-doubling (p, q) and spin–rotation constants (γ _Π, γ _Σ)] are evaluated up to second order (via SO/L couplings with several excited states) using a multireference configuration interaction (MRCI) method, a Breit–Pauli Hamiltonian and 6-311++(2d,2pd) basis sets. Hyperfine constants of magnetic and electric type [Frosch–Foley (a, b, c, d) and nuclear quadrupole (eQq ₀, eQq ₂)] are studied with density functional methods and various basis sets. Magnetic dipole moments (parameterized via g-factors) are calculated in second order like the fine structure constants. The situation is somewhat complex for X²Π since no less than five different g’s have to be evaluated in second order. In general, our results are in good agreement with those reported in the literature, mostly limited to the ground state. Our calculations confirm that, at equilibrium, all second-order properties are dominated by the couplings between the electronic states X and A.     

Average (Recommended) Half-Life Values for Two-Neutrino Double-Beta Decay

All existing "positive" results on two-neutrino double-beta decay in different nuclei were analyzed. Using procedure recommended by Particle Data Group weighted average values for half-lives of ⁴⁸Ca, ⁷⁶Ge, ⁸²Se, ⁹⁶Zr, ¹⁰⁰Mo, ¹⁰⁰Mo-¹⁰⁰Ru (0⁺ ₁), ¹¹⁶Cd, ¹⁵⁰Nd and ²³⁸U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of ¹²⁸Te and ¹³⁰Te are proposed. We recommend to use these results as the most precise and reliable values for half-lives at this moment.     

Global fittings of NNO and NNO vibrational-rotational line positions using the effective Hamiltonian approach

An effective Hamiltonian built up to sixth order in the Amat-Nielsen ordering scheme describing all rovibrational energy levels in the ground electronic state and containing in explicit form all resonance interaction terms due to the approximate relations between harmonic frequencies ω₁≈2ω₂ and ω₃≈4ω₂ was applied to model the observed rovibrational line positions (collected from the literature) of ¹⁴N¹⁵N¹⁶O and ¹⁵N¹⁴N¹⁶O isotopologues of nitrous oxide. For ¹⁴N¹⁵N¹⁶O, 124 effective Hamiltonian parameters were fitted to near 28 000 observed line positions covering the 0.8-8860 cm⁻¹ spectral range. The RMS of the weighted fit is 0.00126 cm⁻¹ and dimensionless standard deviation is 1.48. For ¹⁵N¹⁴N¹⁶O, 121 effective Hamiltonian parameters were fitted to more than 31 000 observed line positions covering the same spectral interval. The RMS of the weighted fit is 0.00185 cm⁻¹ and dimensionless standard deviation is 1.85. In both cases the models describe all available line positions with precision compatible to the measurement uncertainties. A number of local resonance perturbations was found and discussed. Among these perturbations there are interpolyad resonance Coriolis interactions. A comparison of HITRAN-2008 data with the calculations based on the fitted models is presented.     

Studies on some mixed pyrido-phenol donor ligands as sensitisers for terbium (III)

Incorporation of the 2-(2-hydroxyphenyl)-pyridine system into aza-crown systems produces novel ligands for lanthanide ions and can act as sensitising antennae for terbium (III) ions.     

Upconverted VUV luminescence of Nd and Er doped into LiYF4 crystals under XeF-laser excitation

The upconverted VUV (185 nm) and UV (230 and 260 nm) luminescence due to 5d-4f radiative transitions in Nd³⁺ ions doped into a LiYF₄ crystal has been obtained under excitation by 351/353 nm radiation from a XeF excimer laser. The maximum upconversion efficiency, defined as the ratio of intensity for 5d-4f luminescence to overall intensity for 5d-4f and 4f-4f luminescence from the ⁴D_3/2 Nd³⁺ level, has been estimated to be about 70% under optimal focusing conditions for XeF laser radiation. A redistribution of intensity between three main components of 5d-4f Nd³⁺ luminescence is observed under changing the excitation power density, which favors the most long-wavelength band (260 nm) at higher excitation density level. The effect is interpreted as being due to excited state absorption of radiation emitted. The upconverted VUV and UV luminescence from the high-lying ²F(2)_7/2 4f level of Er³⁺ doped into a LiYF₄ crystal has also been obtained under XeF-laser excitation the most intense line being at 280 nm from the spin-allowed transition to the ²H(2)_11/2 4f level of Er³⁺, but the efficiency of upconversion for Er³⁺ emission is low, less than 5%.     

CASPT2 study on low-lying states of HBS+ and HSB+ cations

Some low-lying states of the nine-valence-electron systems HBS⁺ and HSB⁺ cations have been studied by large-scale theoretical calculations using three methods CASSCF, CASPT2, and DFT B3LYP with the contracted atomic natural orbital and cc-pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces were optimized and the energies were calculated. The potential energy curves of isomerization reactions between HBS⁺ and HSB⁺ were calculated as a function of HBS bond angle. The calculated results indicated that the ground-state HBS⁺ is linear, while the ground-state HSB⁺ is bent, which is in contradiction to Walsh's rules predicting linear structures for the HXY systems containing 10 or less valency electrons.     

New analysis of the Comet-Tail (AΠi − XΣ) system in the CO isotopic molecule

The emission spectra of the 0-2, 4-2, and 6-1 bands of the Comet-Tail (A²Π_i − X²Σ⁺) system in the ¹⁴C¹⁶O⁺ isotopic molecule, comprising nearly 600 lines, have been recorded and analyzed for the first time. The spectra have been photographed under high resolution by using conventional spectroscopy, and it was possible to separate and observe most of the lines of all the 12 branches of this transition. The reduction of the individual bands’ spectra has been performed by nonlinear least-squares procedure and by means of effective Hamiltonians of Brown et al. the rovibronic structure parameters have been obtained. The currently investigated bands of the Comet-Tail system and the earlier analyzed bands of the A − X and B − A systems in the ¹⁴C¹⁶O⁺ molecule have been merged together. The results of this global fit made it possible to derive a new set of the equilibrium molecular constants for the A and X states. Then the RKR potential curve parameters for both A and X states and Franck-Condon factors as well as r-centroids for the A − X transition have been calculated for the ¹⁴C¹⁶O⁺ molecule.     

Verteilungskoeffizienten von Ag,In, Re,Au, Hg,Tl, Pb und Bi in Salpetersäure-Methanol-Gemischen

Der Anionenaustausch unter Verwendung von Salpetersäure-Methanol-Gemischen ist in den letzten Jahren von einer Anzahl von Autoren untersucht worden [1, 2, 3, 4]. In einer früheren Arbeit hatten wir bereits auf seine praktisehc Anwendbarkeit für die Trennung der SK hingewiescn [5]. In der vorliegenden Arbeit werden von uns die Verteilungs-koeffizienten von Ag, In, Re, Au, Hg, Tl, Pb und Bi angegeben und Beispiele für mögliche Trennungen angeführt.