EER studies of the single quantum well GaAs/AlxGa1-xAs electrode/nonaqueous solution interface

The interfacial behavior of the single quantum well (SQW) GaAs/AlxGa1-xAs electrode in HQ/BQ and Fc/Fc(+) electrolytes was characterized respectively by studying the quantum confined Stark effect and Franz-Keldysh oscillation with electrolyte electroreflectance spectroscopy. The interaction of the surface state of the SQW electrode with redox species and its effects on the distribution of external bias at the interface of the SQW electrode are discussed.

能级填充对量子阱光学性质的影响

在特殊设计的三势垒双势阱结构中,利用来自发射极的电子注入和电子向收集极的共振隧穿逃逸调控量子阱不同子能级上的填充状态,发现激发态上的电子占据起抑制量子限制Stark效应的作用.在极低偏压下,量子阱中少量过剩电子诱发了用简单带-带跃迁无法解释的光致发光光谱行为.……

掺铒硅发光的晶场分裂

测量了掺铒硅的高分辨光致发光光谱，得到9条铒发光分裂谱线。利用群对称理论指出9条谱线来自Er~(3+)中~4I_(13/2)到~4I_(15/2)光跃迁在T_d晶场下的分裂。Er~(3+)的第一激发态~4E_(13/2)最低能量的两个Stark能级为Γ_8,Γ_6(能量递增)，它们到基态~4I_(15/2)相应晶场Stark能级的允许辐射跃迁为9条谱线。硅

多量子阱自电光效应器件及其负阻特性

研究了GaAs/AlGaAs多量子阱结构的电场光调制特性,测量了光反射谱、光电流谱和光电流电压特性。结果表明,在I-V特性中存在光电流负微分电阻区。由这种多量子阱材料制备的自电效应器件(SEED)观察到明显的量子限制Stark效应。

InGaAs/InAlAs多量子阱电吸收光调制器

用国产MBE设备生长出与InP衬底晶格匹配的InGaAs/InAlAs多量子阱材料，并对材料的量子限制Stark效应及其与光偏振方向有关的各向异性电吸收特性进行研究。用该种材料制作的脊波导结构电吸收调制器在2.4V驱动电压下实现了20dB以上消光比，光3dB带宽达3GHz。

超晶格微带电子态随电场演化过程的电解液电反射谱研究

利用电解液电反射谱研究了In_(0.2)Ga_(0.5)As/GaAs短周期超晶格中微带电子态随电场的演化过程,不仅清楚地观察到弱场Franz-Keldysh效应和强场Wannier-Stark局域化效应,面且观察到了从弱场过度到强场过程中Franz-Keldysh效应和Wannier-Stark局域化效应互相竞争的现象.

稀薄气体效应对高超声速驻点热流的影响

在自由分子流和连续介质的高超声速驻点热流经典解的基础上，通过无量纲分析给出了适用于整个流动领域的高超声速驻点热流公式即 ，其中 ， 为来流Knudsen数，轴对称情况 ，二维情况 。上述关系与Rose和Stark、Koppenwallner、Metcalf等轴对称、圆柱和球柱的高超声速稀薄气体实验数据相符。对比DSMC方法计算得到的高超声速非平衡稀薄气体圆柱和圆球绕流驻点热流(樊菁和沈青 1994, Dogra等 1991)，证明上述关系在热力学和化学非平衡效应显著情况下也是适用的。

Autler-townes splitting in the multiphoton resonance ionization spectrum of molecules produced by ultrashort laser pulses

We report for the first time the proper conditions to observe Autler-Townes splitting (ac-Stark splitting) from vibrationally coherent states belonging to the different electronic terms of a diatomic molecule. Wave packet dynamics simulations demonstrate that such a process is feasible by multiphoton resonance ionization of the molecule Na-2 with a single ultrashort intense laser pulse. With the ultrahigh time resolution of a femtosecond laser pulse, one can directly measure the absolute value of the transition dipole moment between any kinds of molecular states by this kind of Autler-Townes splitting, which is a function of the internuclear distance R.

Control of chemical reaction in high-intensity laser field

The prospects of control chemical reaction in high-intensity laser field are talked about here, and some experimental and theoretical designs are reviewed and discussed also.

Electronic structures and chemical bonding in 4d transition metal monohalides

Bond distances, vibrational frequencies, dipole moments, dissociation energies, electron affinities, and ionization potentials of NIX (XM = Y-Cd, X = F, Cl, Br, I) molecules in neutral, positively, and negatively charged ions were studied by density functional method, B3LYP. The bonding patterns were analyzed and compared with both the available data and across the series. It was found that besides ionic component, covalent bonds are formed between the 4d transition metal s, d orbitals, and the p orbital of halogen. For both neutral and charged molecules, the fluorides have the shortest bond distance, iodides the longest. Although the opposite situation is observed for vibrational frequency, that is, fluorides have the largest value, iodides the smallest. For neutral and anionic species, the dissociation energy tends to decrease with the increasing atomic number from Y to Cd, suggesting the decreasing or weakening of the bond strength. For cationic species, the trend is observed from Y to Ag.

Density functional studies of diatomic LaO to LuO

Bond distances, vibrational frequencies, electron affinities, ionization potentials, dissociation energies and dipole moments of the title molecules in neutral, positively and negatively charged ions were studied by use of density functional method. Ground electronic state was assigned for each molecule. The bonding patterns were analyzed and compared with both the available data and across the series. It was found that besides ionic component, covalent bonds are formed between the metal s, d and f orbitals and oxygen p orbitals. Contrary to the well known lanthanide contraction, the bond distance is not regular from LaO to LuO for both neutral and charged molecules. An obvious population at 5d orbital was observed through the lanthanide series. 4f electrons also participate the chemical bonding for CeO to NdO and TbO to TmO. For EuO, GdO, YbO and LuO, 4f electrons tend to be localized. The spin multiplicity is regular for neutral and charged molecules. The spin multiplicity of the charged molecules can be obtained by -1 (or +1 for TbO+, DyO+, YbO- and YbO+) compared with the corresponding neutral molecules.

Networks with hexagonal circuits in co-ordination polymers of metal ions (Zn-II, Cd-II) with 1,1 '-(1,4-butanediyl)bis(imidazole)

Three new compounds, [ZnL1.5(H2O)(SO4)]. 6H(2)O 1, [ZnL1.5(H2O)(2)][NO3](2). 2H(2)O 2 and [CdL1.5(H2O)(2)(SO4)]. 4H(2)O 3 were obtained from self-assembly of the corresponding metal salts with 1,1'-(1,4-butanediyl)bis(imidazole) (L). In both 1 and 2 zinc ion is five-co-ordinated, showing a less-common trigonal bipyramidal co-ordination polyhedron, while cadmium ion of 3 is six-co-ordinated with a common octahedral arrangement. The sulfate ions of 1 and 3 are co-ordinated, however the nitrate ions of 2 are not. Each of the three compounds is composed of a (6, 3) network with the hexagonal smallest circuit containing six metal ions and six L; each L is co-ordinated to two metal ions, acting as a bridging ligand. In 1 the 2-D sheet of (6, 3) networks is interpenetrated in an inclined mode by symmetry related, identical sheets to give an interlocked 3-D structure, while the (6, 3) networks of both 2 and 3 stack in a parallel fashion to construct frameworks having channels.

cis-Dichloridobis(1,10-phenanthroline-kappa N-2,N ')-cadmium(II) hemihydrate

The title compound, [ CdCl2( C12H8N2)(2)]center dot 0.5H(2)O, crystallizes with two independent complex molecules and one water molecule in the asymmetric unit. The Cd atoms in both independent complexes display a distorted octahedral coordination geometry formed by four N atoms from two phenanthroline ligands and two Cl atoms. In the crystal structure, pi-pi stacking interactions link complexes in two symmetry- independent ladders parallel to the c axis. Intermolecular O-H center dot center dot center dot Cl hydrogen bonds stabilize the crystal packing.