二十面体群拉曼和超位曼张量的计算

本文简单介绍了计算张量的不变式－协变式方法,以及根据此原理所编程序的设计思想,并在附录中给出了二十面体群的Ｒａｍａｎ、Ｈｙｐｅｒ－Ｒａｍａｎ对称张量和非对称（α、β、γ）张量。     

二十面体群C-G系数计算

本文简要介绍了计算Ｃ Ｇ系数的生群元矩阵方程法，给出计算二十面体群Ｃ Ｇ系数时采用的简化计算方法，并给出了Ⅰ群Ｃ Ｇ系数的计算结果。     

含有五度旋转轴点群的超拉曼张量的计算

超拉曼散射涉及晶格振动, 因此它需要由动态张量来描述。根据坐标积与张量元在对称操作下的变换形式相同的原理, 通过C语言编程, 计算了属于不同不可约表示的动态张量, 并列出了含有五度旋转轴点群的三阶超拉曼张量。     

量子多体系统的线性张量重正化群方法

文章简述了数值重正化群方法的历史发展,包括威耳逊（Wilson）的数值重正化群算法,S.R.White的密度矩阵重正化群方法,以及近期迅速发展的处理强关联量子系统的几种张量网络态与张量网络算法.在此基础上,文章重点介绍了作者最近提出的用于研究量子多体系统热力学性质的线性张量重正化群方法,以及该方法在一维和二维量子系统中的应用.     

Al—Fu—Fe二十面体准晶的深过冷研究

通过循环过热净化研究Ａｌ－Ｃｕ－Ｆｅ合金毛织品 Ａｌ６５Ｃｕ２０Ｆｅ１５合金液的深过冷，采用循环过热净化法净化Ａｌ６５Ｃｕ２０Ｆｅ１５合金液，获得了９８Ｋ的过冷度，并制备出直径为６ｍｍ的高纯度的Ａｌ－Ｃｕ－Ｆｅ二十面体准晶球。随着Ａｌ６５Ｃｕ２０Ｆｅ１５合金液过冷度的不同，Ａｌ６５Ｃｕ２０Ｆｅ１５合金液的第一形核相也发生变化。     

稳态Cu-Zr二十面体团簇电子结构的密度泛函研究

采用第一原理对以Cu为心的低能稳态Cu_nZ_(r13-n)(n=6,7,8,9)二十面体团簇的电子结构进行计算,结果表明:同一化学组分下,以Cu为心的Cu-Zr二十面体团簇中出现的同类原子聚集现象可以增强团簇的稳定性,降低费米能级(EF)上的电子数N(EF),这为低能稳态团簇拥有较小的N(EF)提供了深层次的理论解释.进一步的差分电子密度与Mulliken布居分析得知,Cu-Zr二十面体中共价键与离子键共存,成键态与反键态共存,且团簇在形成时壳层Zr与中心Cu原子是电子的提供者,壳层Cu是电子的获得者.该电荷转移方向是金属玻璃中以Cu为心的Cu-Zr二十面体团簇普遍遵循的规律,不随团簇的化学序参数及化学组分的变化而变化.计算的红外振动谱为实验上准确表征不同二十面体原子团提供了一种新的思路.     

作为统一张量的Raman张量的程序化计算

作为统一张量的Ｒａｍａｎ张量的程序化计算郝伟廖理几金泽宸＊刘凤艳（北京工业大学应用物理系北京１０００２２）（＊中国农业大学基础科技学院北京１０００９４）ＰｒｏｇｒａｍｆｏｒＣａｌｃｕｌａｔｉｎｇＲａｍａｎＴｅｎｓｏｒｓａｓＵｎｉｆｉｅｄＴｅｎｓｏｒｓ...     

易解石族矿物的Raman光谱和光致发光谱研究

测定并讨论了中国白云鄂博矿区变生及退火晶态易解石族矿物Ｒａｍａｎ光谱和光致发光谱,与退火晶质矿物相比,变生态易解石的Ｒａｍａｎ光谱和光致发光谱的强度降低,谱线宽化弥散,说明在变生过程中,矿物的结构发生畸变,元素分布趋于无序。分析表明,易解石族矿物在５１４．５ｎｍ激光激发下的所有光致发光谱峰均出自Ｎｄ＾３＋的辐射跃迁。     

Hyper Raman spectra calculated in a time-dependent Hartree–Fock method

Hyper Raman scattering (HRS) of the benzonitrile (BN) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) molecules is studied by means of ab initio calculations. The computational procedure employs a recently developed methodology for the analytic calculations of frequency-dependent polarizability gradients of arbitrary order, including perturbation dependent basis sets. The result are compared to normal Raman scattering (NRS) and coherent anti-Stokes Raman scattering (CARS) that previously have been studied using the same technology. It is found that some suppressed or silent modes in CARS and NRS spectra are clearly seen in HRS, and that although under general excitation conditions the HRS intensities are much lower than for CARS and NRS, HRS provides complementary information useful for target identification.     

Raman tensor elements for multiferroic BiFeO3 with rhombohedral R3c symmetry

A quantitative assessment of the Raman spectrum emitted from a coarse‐grained polycrystal of multiferroic BiFeO₃ has been carried out by means of a polarized Raman microprobe. The dependence of the intensity of Raman phonon modes has been first theoretically modeled as a function of crystal rotation. Then, the Raman tensor elements have been experimentally determined from the analysis of the A_g and E_g vibrational modes. Copyright © 2009 John Wiley & Sons, Ltd.     

结合异常样本检测的汽油族组成拉曼光谱分析

汽油族组成不仅决定了汽油品质,同时直接关系到燃烧尾气对环境的影响。文章成功地将拉曼光谱分析技术应用于汽油族组成的定量分析。通过对校正集进行异常样本检测,剔除个别异常样本,有效地提高了偏最小二乘的模型精度,得到了较好的预测效果。芳烃含量、烯烃含量和氧含量的标准预测误差分别达到了0.23,0.52和0.143,其预测复相关系数分别达到了0.987,0.927和0.971。实验结果表明：采用拉曼光谱分析技术可以有效的解决汽油族组成的定量分析问题,其分析精度显著高于近红外光谱法与多维气相色谱法;同时也适用于汽油生产过程中的在线分析。     

Letter: Review of the Definitions of the Bel and Bel-Robinson Tensors

Since the Bel and Bel-Robinson tensors were discovered in the 1950's several equivalent but different definitions have appeared in the literature. This note presents the different definitions in historical order and suggests Bel's 1962 definition to be taken as the foundation.     

Formation Mechanism and Binding Energy for Icosahedral Central Structure of He1+3 Cluster

The formation mechanism for the icosahedral central structure of the He1 13 cluster is proposed and its total energy curve is calculated by the method of a Modified Arrangement Channel Quantum Mechanics. The energy is the function of separation R between two nuclei at the center and an apex of the icosahedral central structure. The result of the calculation has shown that the curve has a minimal energy -37.5765 (a.u.) at R = 2.70ao. The binding energy of He 13 with respect to He 12He was calculated to be 1.4046 a.u. This means that the cluster of He 13 may be formed in an icosahedral central structure with strong binding energy.     

Raman spectra and phase composition of MnGeO3 crystals

MnGeO₃ single‐crystal samples have been synthesized by optical zonal melting and spontaneous crystallization. X‐ray crystal analysis showed the first sample to be a two‐phase one with phase ratio as follows: 17% – monoclinic C2/c, and 83% – orthorhombic Pbca; the phase ratio of the second sample was unknown. Raman spectra have been produced for these samples. Lattice dynamics has been simulated and polarization dependencies of lines' intensities have been analyzed to interpret experimental Raman spectra and to attribute lines to the spectra of monoclinic and orthorhombic phases. Copyright © 2015 John Wiley & Sons, Ltd.     

Formation Mechanism and Binding Energy for Icosahedral Central Structure of He13^＋ Cluster

The formation mechanism for the icosahedral central structure of the He13^ cluster is proposed and its total energy curve is calculated by the method of a Modified Arrangement Channel Quantum Mechanics. The energy is the function of separation R between two nuclei at the center and an apex of the icosahedral central structure. The result of the calculation has shown that the curve has a minimal energy -37.5765 (a.u.) at R=2.70ao. The binding energy of He13^ with respect to He^ 12He was calculated to be 1.4046 a.u. This means that the cluster of He13^ may be formed in an icosahedral central structure with strong binding energy.