O2分子激发态a1Δg和b1Σ+g态的分析势能函数

以aug-cc-pVQZ,cc-pV5Z,6-311++g（d,p）和6-311++g（3df,3pd）等为基函数,采用多组态相互作用（MRCI）方法对O₂分子最低的两个激发态¹Δ_g和¹Σ⁺_g的平衡结构、谐振频率和势能曲线进行了计算.并选用Murrell-Sorbie势能函数对曲线进行拟合,利用拟合的参数值计算出了力常数和光谱数据.结果表明计算值与实验值符合较好. 关键词： MRCI 势能函数 力常数 光谱数据     

Eley–Rideal reaction dynamics between O atoms on β-cristobalite (1 0 0) surface: A new interpolated potential energy surface and classical trajectory study

We present a theoretical study of the collisions of atomic oxygen with O-precovered β-cristobalite (1 0 0) surface. We have constructed a multidimensional potential energy surface for the O₂/β-cristobalite (1 0 0) system based mainly on a dense grid of density functional theory points by using the interpolation corrugation-reducing procedure. Classical trajectories have been computed for quasithermal (100–1500 K) and state-specific (e.g., collision energies between 0.01 and 4 eV) conditions of reactants for different O incident angles (θ_v). Atomic sticking and O_2(adsorbed) formation are the main processes, although atomic reflection and Eley–Rideal (ER) reaction (i.e., O₂ gas) are also significant, depending their reaction probabilities on the O incident angle. ER reaction is enhanced by temperature increase, with an activation energy derived from the atomic recombination coefficient (γ_O(θ_v = 0°, T)) equal to 0.24 ± 0.02 eV within the 500–1500 K range, in close agreement with experimental data. Calculated γ_O(θ_v = 0°, T) values compare quite well with available experimental γ_O(T) although a more accurate calculation is proposed. Chemical energy accommodation coefficient β_O(T) is also discussed as a function of ER and other competitive contributions.     

Manufacturing of Volumetric Glass–Based Composites with Single‐ and Double‐QD Doping

Quantum dot (QD)‐based light‐emitting materials are gaining increased attention because of their easily tunable optical properties desired for various applications in biology, optoelectronics, and photonics. However, few methods can be used to manufacture volumetric materials doped with more than one type of QD other than QD‐polymer hybrids, and they often require complicated preparation processes and are prone to luminescence quenching by QD aggregation and separation from the matrix. Here, simultaneous doping of a volumetric glass‐based nanocomposite with two types of QDs is demonstrated for the first time in a single‐step process using the nanoparticle direct doping method. Glass rods doped with CdTe, CdSe/ZnS, or co‐doped with both QDs, are obtained. Photoluminescence and lifetime experiments confirm temperature‐dependent double emission with maxima at 596 and 720 nm with mean lifetimes up to 16 ns, as well as radiative energy transfer from the short wavelength–emitting QDs to the long wavelength–emitting QDs. This approach may enable the simple and cost‐efficient manufacturing of bulk materials that produce multicolor luminescence with cascade excitation pumping. Applications that could benefit from this include broadband optical fiber amplifiers, backlight systems in LCD screens, high‐power LEDs, or down‐converting solar concentrators used to increase the efficiency of solar panels.     

Scalar Tensor Cosmology With Kinetic,Gauss-Bonnet and Nonminimal Derivative Couplings and Supersymmetric Loop Corrected Potential

We discuss a particular four-dimensional cosmology based on non-minimal scalar tensor theories characterized by a supersymmetric loop corrected potential and a Hubble parameter defined as a function of the scalar field. Power-law solutions are obtained in the FRW background giving rise to acceleratedly expanding universe characterized by a scale factor and a scalar field depending both on the non-minimal coupling parameter $\xi$. Based on SNeIa data and on Hubble data X-ray gas mass fraction measurements, we find $0.116<\xi <0.225$ which results on a universe dominated by vacuum energy.     

YAB晶体中Yb3+到Er3+的能量传递

1.55 μm波段是光通讯的一个重要波段,而且对人眼安全,有高的大气透过率,因此可以广泛应用于通讯和遥感测距等领域。由于Er³⁺离子对商品化的InGaAs激光二极管的抽运波长不能有效吸收,因此一般通过在基质中共掺杂Yb³⁺和Er³⁺离子来获得1.55 μm波段激光输出。采用助熔剂法生长了不同Yb³⁺和Er³⁺掺杂浓度的YAl₃(BO₃)₄(YAB)晶体。运用速率方程模型研究了晶体中Yb³⁺到Er³⁺能量传递过程,得到了根据Yb³⁺离子的荧光寿命计算能量传递系数的简单计算公式。计算了不同掺杂离子浓度的YAB晶体中的能量传递系数等相关参数。结果表明,在YAB晶体中,Yb³⁺到Er³⁺能量传递非常有效,YAB晶体可以作为一种能获得1.55 μm激光输出的良好介质材料。     

Mechanics of atoms interacting with a carbon nanotorus: optimal configuration and oscillation behaviour

In this paper, we investigate a carbon nanotorus as a caged molecular structure interacting with an atom. Assuming that the atom is located along the central axis perpendicular to the torus, the interaction energy of the system is determined using the continuum approximation together with the Lennard-Jones potential. This approach avoids the intensive computational calculations that are involved in other modelling approaches. Numerical results are presented in terms of dimensionless variables. The results show that the optimal major radius of the torus has a linear relationship with its minor radius when the atom is symmetrically situated along the torus axis. When the atom is offset from this axis, the minimum energy location shifts away from the centre as the ratio of the major and minor radii exceeds the value of 0.90. Finally, the oscillatory behaviour for the carbon atom is investigated. Our findings predict a novel nano-oscillator which can produce frequencies in the gigahertz range.     

Comparison of 1D, 2D and 3D quench onset simulations

Measured and simulated minimum quench energies (MQE) for short samples are doubtful when estimating disturbance tolerance of an impregnated superconducting magnet. If measurements are performed at liquid cryogen, the cooling provided by the cryogen causes MQE to be high. At a conduction-cooled system, the transverse heat conduction is neglected causing low MQE. Even though these conditions can be artificially brought closer to the ones in an impregnated magnet, it is difficult to estimate by short-sample measurement the MQE of a superconducting coil. These similar difficulties are present at simulations. On the other hand, 1D and 2D measurements and simulations can be used, e.g., to compare wires or consider effect of insulation layer thickness, but according to the results only in a rough quantitative way. In this paper, we compare MQE and normal zone propagation velocity simulations of an MgB₂ wire with 1D, 2D and 3D finite element method models to focus on the different results given by the models employing different dimensions.     

NO分子的基态(X~2П)和激发态(a~4П and B~2П)光谱常量和振动能级的计算(英文)

本文使用完全活性空间自洽场/多组态相互作用(CASSCF/MRCI)理论,以cc-pVDZ为基组,计算了NO分子基态(X2Π)和激发态(a4ПandB2П)的平衡结构和单点能扫描曲线.采用最小二乘法拟合了Murrell-Sorbie函数,得到了NO分子的解析势能曲线,并利用Rydberg-Klein-Rees方法,计算得到的NO分子相应态的谐振频率和其它的光谱数据(ωe、αe、ωeχe、βe)与实验值十分一致,和其它理论计算方法进行比较,发现该方法有更好的准确性.以得到的解析势能函数为基础,求解NO分子核运动的一维径向Schrdinger方程,获得了更高振动态的振动能级.