Fe:LiNbO3和(Fe,Tb):LiNbO3晶体中入射光强

用一种新的测量方法在不同入射光强下同时观测了Fe:LiNbO3和(Fe,Tb):LiNbO3晶体中光致折射率变化Δns、吸收系数α和光电导σph与入射光强I的依赖关系, 并从理论上对观测结果给予了初步解释。     

Li2K(IO3)3与Li2NH4(IO3)3的晶体结构

本文用X射线粉末法测定了Li₂K(IO₃)₃与Li₂NH₄(IO₃)₃的晶体结构和原子参数。发现Li₃K(IO₃)₃,Li₂NH₄(IO₃)₃与Li₂Rb(IO₃)₃同晶型,属单斜晶系,空间群为P2₁/α,每个单胞含有四个化合式量。室温的点阵常数分别为α=11.198?,b=11.046?,c=8.254?,β=111.53°,及α=11.327?,b=11.078?,c=8.341?,β=111.87°。讨论了二元化合物的形成与离子半径的关系。 关键词：     

10－5000 伏下电子被多原子分子CF4, CF3H, C2F4, C2F6, 及 C2H3F3散射总结面的计算

利用可加性规则和光学势方法计算了能量在10-5000 eV范围内电子被多原子分子CF4, CF3H, C2F4, C2F6, 及 C2H3F3的总结面，并与已有的实验结果和理论计算进行了比较，与这些结果符合得很好。对于CF4, CF3H, C2F4, C2F6, 及 C2H3F3在1000eV以上没有实验数据，本文对实验研究提供了对比和预测的数据。     

β-C3N4,β-Si3N4和β-Ge3N4的能带结构

采用基于密度泛函理论的线性丸盒轨道原子球近似(LMTO-ASA)从头计算方法,研究了β-C₃N₄,β-Si₃N₄和β-Ge₃N₄的能带结构,得到了它们的能隙分别为:4.1751,5.1788和4.0279eV。对于β-C₃N₄,由于N的部分2p电子占据了非键轨道,禁带宽度较窄;对于β-Si₃N_{4关键词：}     

YAlO3:Nd3+的吸收光谱

从0.33—5.7μm的波长范围内系统地测定了温度为10K、90K和30OK时YAlO₃:Nd³⁺的吸收光谱,定出Nd³⁺在晶体场作用下的斯塔克(Stark)子能级。并在10K到663K的温度范围内,观察了部分光谱线的温度效应,得到一些有意义的结果。 关键词：     

On the Study of Resonance Interactions and Splittings in the PH3 Molecule: ν1, ν3, ν2+ν4, and 2ν4 Bands

The high-resolution (0.005 cm⁻¹) Fourier transform infrared spectrum of PH₃ is recorded and analyzed in the region of the fundamental stretching bands, ν₁ and ν₃. The ν₂+ν₄ and 2ν₄ bands are taken into account also. Experimental transitions are assigned to the ν₁, ν₃, ν₂+ν₄, and 2ν₄ bands with the maximum value of quantum number J equal to 15, 15, 13, and 15, respectively. a₁-a₂ splittings are observed and described up to the value of quantum number K equal to 10. The analysis of a₁/a₂ splittings is fulfilled with a Hamiltonian model which takes into account numerous resonance interactions among all the upper vibrational states.     

The 2ν1, 2ν2 and 2ν3 overtones of FClO3

The infrared spectra of the 2ν₁, 2ν₂ and 2ν₃ overtones of perchloryl fluoride, FClO₃, have been recorded at high resolution using monoisotopic pure samples. Four symmetric top species have been investigated: F³⁵Cl¹⁶O₃, F³⁷Cl¹⁶O₃, F³⁵Cl¹⁸O₃ and F³⁷Cl¹⁸O₃. The v_i = 2, i = 1, 2, 3 vibrationally excited states are totally symmetric, so these overtones correspond to parallel bands of medium/weak intensity, centered from 2010 to 2120 cm⁻¹ (2ν₁), from 1390 to 1430 cm⁻¹ (2ν₂) and from 1070 to 1100 cm⁻¹ (2ν₃). Most of the bands are unperturbed and their analysis was straightforward. The band origins, the rotational and centrifugal molecular constants in the v₁ = 2, v₂ = 2 and v₃ = 2 states have been determined, with standard deviations of the fits from 0.00024 to 0.00067 cm⁻¹. The 2ν₁ overtones of F³⁵Cl¹⁶O₃ and F³⁷Cl¹⁶O₃ are perturbed by an A₁/E Coriolis resonance between the v₁ = 2 state and one E component of the v₄ = 1, v₆ = 2 manifold. The 2ν₂ of F³⁷Cl¹⁸O₃ is perturbed by the same kind of interaction involving the v₁ = v₆ = 1 (E) state, at about 1396 cm⁻¹. In these bands the resonance is localized on rotational levels with specific J and K values. As a consequence, a few transitions of the perpendicular bands involving the interacting levels could be identified in the spectra. A simultaneous fit of the transitions assigned to the dyads has been performed and the parameters of the excited states have been determined, including the high order Coriolis interaction coefficient . The anharmonic constants x₁₁, x₂₂, x₃₃ of all the studied isotopologues of FClO₃, x₄₆ of F³⁵Cl¹⁶O₃, x₄₆ + g₄₆ of F³⁷Cl¹⁶O₃ and x₁₆ of F³⁷Cl¹⁸O₃, have been derived.     

The (ν1, ν4, ν2+ν3, ν3+ν5) Polyad of D3SiF around 1600 cm, Studied by High-Resolution FTIR Spectroscopy

The ν₁ (A₁, 1578.31 cm⁻¹)/ν₄(E, 1615.17 cm⁻¹) Si-D stretching dyad of D₃SiF has been studied by FTIR spectroscopy with a resolution of 2.4×10⁻³ cm⁻¹. Only weak interactions of Coriolis (ΔK=±1, Δ?=±1) and α resonance (ΔK=±2, Δ?=?1) type between ν₁ and ν₄, and of ? (2,−4) type within ν₄, were revealed. However, the v₁=1 and v₄=1 levels were found to be severely perturbed by the v₃=v₅=1 (E, 1590.37 cm⁻¹) and v₂=v₃=1 (A₁, 1604.25 cm⁻¹) states. These perturbations are observable only near level crossings involving strong Coriolis and α interactions. The energy structure within these perturbers is severely complicated by strong Coriolis and α resonances and by ? (2, 2), ? (2,−1), and ? (2,−4) interactions as already revealed by the ν₂(A₁, 710.16 cm⁻¹) and ν₅ (E, 701.72 cm⁻¹) fundamentals. Interactions of the perturbing states with the ν₁/ν₄ dyad are particularly evident in local crossings. In total, 12 transitions belonging to the dark states and 68 perturbation-allowed transitions within the ν₁/ν₄ dyad have been detected among the more than 5000 transitions that have been assigned for the ν₁/ν₄ dyad, with J_max and K_max of 50 and 30, respectively. Altogether about 85% of the assigned transitions were fitted with a standard deviation of 0.221×10⁻³ cm⁻¹, leading to 61 parameters of the interacting polyad.     

用会聚束电子衍射测定LiZnTa3O9,LiCaTa3O9的对称性

本文用会聚束电子衍射方法测定了我们生长的新晶体LiZnTa₃O₉和LiCaTa₃O₉的对称性,得出LiZnTa₃O₉晶体属三方晶系,点阵参数a=0.557nm,a=56.12°,点群为3m,空间群为R3c。LiCaTa₃O₉晶体属四方晶系,点阵参数a=0.778nm,c=0.783nm,点群为4/mmm。 关键词：     

Acousto-optic Q-switched laser performances of Er3+:Yb3+:LuAl3（BO3）4 crystal at 1.5-1.6 μm

Diode-pumped acousto-optic Q-switched pulse laser at 1.5-1.6 μm is obtained in an Er3+:Yb3+:LuAl3 (BO3)4 crystal. Single-pulse laser operation with slope efficiency of 14% and threshold of approximately 100 mW is realized at an average absorbed pump power of 314 mW and repetition frequency of 20 kHz. Output pulse energy is 67 μJ. The effects of pulse repetition frequency, absorbed pump power, and duty cycle on the wavelength and pulse profile of the Q-switched Er3+:Yb3+:LuAl3(BO3)4 laser are also investigated.     

YAlO3:Nd3+的子能级R1和R2的热移位

实验测定了YAlO₃:Nd³⁺的子能级R₁,R₂的热移位值。研究了单声子项中积分主值的行为,并计入光频支项对子能级热移位的贡献。用包含Raman项、单声子顶、光频支项的公式拟合计算子能级R₁,R₂的热移位,拟合计算值与实验值符合得很好。 关键词：     

SrTiO3表面O2,H2O吸附的UPS,XPS研究

观察到还原SrTiO₃表面三价Ti离子引起的表面态的存在。分析了它在太阳光分解水中所起作用,以及光照在恢复活性中的作用。 关键词：     

Line shifts in the ν2, 2ν2, and ν4 bands of NH3 perturbed by O2

Pressure-induced line shift coefficients have been measured for more than 200 rovibrational lines of NH₃ perturbed by O₂ at room temperature (T = 295 K) in some branches of the ν₂, 2ν₂, and ν₄ bands. These lines with J values ranging from 1 to 13 are located in the spectral range 800-1800 cm⁻¹. Experiments were made with a high-resolution Fourier transform spectrometer. The treatment of vibration-rotation lines includes interference effects caused by the overlapping of lines. The O₂ pressure-induced shift coefficients have been derived from the non-linear least-squares multi-pressure fitting technique. The results illustrate a vibrational dependence of line shifts with vibrational quantum number. Most of the measured shifts are negative in the ν₄ band. They are positive for the ν₂ and 2ν₂ bands. The measured shift coefficients are compared with previous measurements and with those calculated from a semiclassical theory based upon the Robert-Bonamy formalism extended to the case of symmetric top molecule with inversion motion. The predictions are generally in satisfactory agreement with the experimental data. Analyses of measured and predicted results illustrate that these shifts mainly originate from the isotropic part of the intermolecular potential.     

High resolution study of AsHD2: Ground state and the three bending fundamental bands ν3, ν4, and ν6

For the first time the infrared spectrum of the AsHD₂ molecule has been measured in the region of the bending fundamental bands ν₃, ν₄, and ν₆ on a Fourier transform spectrometer with a resolution of 0.0024 cm⁻¹ and analyzed. More than 5500 transitions with J^max = 26 have been assigned and used both to obtain “ground state combination differences” and for the determination of upper state ro-vibrational energies of the triad (001000), (000100), and (000001). Rotational parameters including centrifugal distortion coefficients up to octic terms of the ground vibrational state were calculated by fitting more than 500 “ground state combination differences” with J^max and . The obtained set of 24 parameters provides a rms-deviation of 0.00011 cm⁻¹. The upper energies were fitted with 52 parameters of an effective Hamiltonian which takes into account strong resonance interactions between all vibrational states of the triad (001000), (000100), and (000001). The rms-deviation for the energy levels considered in the fit is 0.00014 cm⁻¹.     

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采用分子动力学方法模拟200eV的CH3粒子轰击到不同基底温度的钨样品上,分析了C、H原子在钨表面的沉积、散射及溅射情况,结果表明C、H原子的沉降量均随入射剂量的增加而增加。在基底温度为100K时,相同入射剂量下沉积的C原子最多,而当基底温度为1200K,在入射剂量大于1.5X1016cm-2时,C原子的沉降量小于其它基底温度下的C的沉降量。CH3在轰击样品时发生了分解,各种分解情况随基底温度变化较小,其中不同基底温度下一级分解率在40%上下波动,二级分解在23%左右,而完全分解的CH3在9%左右。C、H原子的散射角主要分布在5°~85°间,散射C原子分布的最大值分布在40%~50°或50°~60°间,散射C原子分布的最小值分布在0°~10°或80°~90°间;而不同基底温度下散射H原子分布的最大值均在40°~50°间,最小值均在0°~10°间。散射C原子的能量在0~140eV之间,散射能量为0~120eV的C原子占散射总量的98%以上,散射C原子平均能量随基底温度的增加而增加,其变化从65.5eV增加到68.5eV;散射H原子的能量也在0~140eV之间,但大约70%的散射H原子能量在40eV以内,散射平均能量随基底温度的增加而减小,其变化从13.92eV减小到13.05eV。     

Pr,Yb,Ho:GdScO3晶体生长及光谱性能

2.7—3.0μm波段激光在很多领域具有重要应用,为探索和发展该波段新型晶体材料,本文采用提拉法生长出Pr, Yb, Ho:GdScO₃晶体,通过共掺入Pr³⁺离子以达到衰减Ho³⁺:⁵I₇能级寿命的目的.采用X射线衍射测试得到了晶体的粉末衍射数据,测量了拉曼光谱,并对晶体的拉曼振动峰进行指认,对Pr, Yb, Ho:GdScO₃晶体的透过光谱、发射光谱和荧光寿命进行表征. Yb³⁺的最强吸收峰在966 nm,吸收峰半峰宽为90 nm;2.7—3.0μm波段最强发射峰在2850 nm,半峰宽为70 nm; Ho³⁺:⁵I₆和⁵I₇能级寿命分别为1094μs和56μs.与Yb,Ho:GdScO₃晶体相比, Yb³⁺的吸收峰和2.7—3.0μm的发射峰半峰宽明显展宽,同时下能级寿命显著减...     

Observation of simultaneous ν1(SF6) + ν3(NF3) and ν2(SF6) + ν3(NF3) transitions enhanced by the resonance dipole-dipole interaction with the ν1 + ν3 and ν2 + ν3 states of the SF6 molecule

IR spectra of the solution of SF₆ molecules in liquid NF₃ at 84 K have been recorded. In a solvent transmission window of 1500–1750 cm⁻¹, two wide absorption bands with pronounced peaks in the high-frequency part are observed. The profile of these bands is explained by the influence of the resonance dipole-dipole (RDD) interaction of the states of the simultaneous transition ν₁(SF₆) + ν₃(NF₃) and ν₂(SF₆) + ν₃(NF₃) with the states (ν₁ + ν₃) and (ν₂ + ν₃) of the SF₆ molecules, respectively. The use of three isotopic modifications ³²SF₆, ³³SF₆, and ³⁴SF₆ has allowed us to vary the resonance detuning and thus to change the strength of the RDD interaction. With the liquid near the melting point being represented as a close-packed cubic crystal, the profile was calculated and its spectral characteristics were determined. The frequencies of the main peaks coincide with the experimental values accurate to the error.     

La2O3对Yb:Y2O3透明陶瓷光谱性能的影响

研究了La₂O₃对Yb：Y₂O₃透明陶瓷光谱性能的影响，添加适量La₂O₃以后，Yb：Y₂O₃透明陶瓷的吸收峰和发射峰的位置不变，但由于La³⁺的离子半径大于Y³⁺的离子半径，在Y₂O₃中引入La³⁺离子后，导致Y₂O₃晶格常数变大，晶场强度变弱，同时降低了Y₂O₃晶体的有序度，致使发射峰强度有所下降，发射截面变小.过量的La₂O₃（x=0.16）造成Yb³⁺激活离子发射强度明显下降；其荧光寿命在添加La₂O₃后总体增大45%—60%. 关键词： 氧化镧 氧化钇 透明陶瓷 光谱性能     

La2/3Ca1/3MnO3/Eu2CuO4/La2/3Ca1/3MnO3磁性隧道结的制备与表征

采用磁控溅射，紫外线光刻和离子束刻蚀制备了La_2/3Ca_1/3MnO₃/Eu₂CuO₄/La_2/3Ca_1/3MnO₃磁性隧道结.通过对获得的磁性隧道结的I-V特性测量，发现非线性的I-V特性，显示结样品的隧穿特性.有趣的是发现在电极材料La_2/3Ca_1/3MnO₃的金属-绝缘体转变温度(Tp)以下，I-V曲线出现一个跳变.随着温度降低，开始出现跳变的临界电流增大，但是跳变都发生在同样的电压下～209mV.当电流增大或减小在跳变点附近出现回滞.这一跳变只发生在铁磁金属态，表明这是一个磁性相关联的效应，可能对应一种新的磁性开关过程.虽然，目前对这一现象背后的物理机理还不清楚，但是，这一现象有可能在未来自旋电子学器件方面具有潜在的应用价值. 关键词： 庞磁电阻 磁性隧道结 开关效应