S7环的振动光谱的理论研究

在从头算层次上采用自洽场ＨＦ方法与杂化的密度泛函Ｂ３ＬＹＰ方法以及基组３－２１＋Ｇ（ｄ）与６－３１＋Ｇ（ｄ）,优化了Ｓ７环ｃｈａｉｒ和ｂｏａｔ分子构型。接着在优化结构基础上,计算了Ｓ７环两种构型的振动光谱、简谐振动模式对称性和红外谱线相对强度。计算结果与实验数据进行了比较。     

Si｛111｝的吸附表面结构

利用低能电子衍射研究了金属和非金属吸附在Ｓｉ｛１１１｝表面的表面结构。结果显示出：对Ａｌ、Ｇａ、Ｂｉ和Ａｕ原子，形成α－Ｓｉ｛１１１｝３×３Ｒ３０°－Ｍ或β－Ｓｉ｛１１１｝３×３Ｒ３０°－Ｍ结构的共价吸附。对Ｌｉ、Ｎａ和Ａｇ原子，形成正离子吸附，全部经高温解吸后，便诱导出Ｓｉ｛１１１｝１×３重构。对Ｔｅ原子，形成负离子吸附，经高温解吸后，便诱导出Ｓｉ｛１１１｝类（１×１）结构。     

在小硅化物SiX~m（X＝Be、B、C、N、O、F、Ne，m＝～4－＋2）中分子成键倾向的从头算研究

此文用从头计算法，在ＨＦ、ＭＰ２、ＭＰ３水平下，使用基组６—３１Ｇ、６—３１＋Ｇ对ＳｉＯ的等电子分子ＳｉＸｍ（Ｘ＝Ｂｅ、Ｂ、Ｃ、Ｎ、Ｐ、Ｎｅ，ｍ＝－４～＋２）进行了几何优化，并计算了相应的平衡几何构型下的振动频率，对ＳｉＯ分子，使用ＱＣＩＳＤ（Ｔ）方法考虑了不同水平下的电子相关效应，并考虑了不同基函数６－３１＋Ｇ和６－３１１＋Ｇ的影响。计算结果表明，所有分子的势能曲线都有稳定的极小值，并且键长与频率在ＨＦ、ＭＰ２、ＭＰ３水平上都呈现出明显的规律性，通过与实验上存在的稳定分子ＳｉＯ相比较，可以预言ＮＳＩｉ－和ＳｉＦ＋比其它分子有较明显的成键可能性，所以，ＮＳｉ－和ＳｉＦ＋有可能形成稳定的分子。     

STM针尖和外电场在Si（111）—7＊7表面单原子操纵中的作用

利用第一性原理的离散变分局域密度泛函方法,采用团簇模型（Ｓｉ３４Ｈ３６－Ｗ１１）来模拟ＳＴＭ操纵（Ｓｉ１１１）－７＊７表面顶角吸附原子的过程,通过分析在进行原子操纵过程中体系的能量与电子云密度分布来研究针尖和外电场的作用。     

在小硅化物SiX^m（X=Be,B,C,N,O,F,Ne,m=～4—＋2）中分子成…

此文用从头计算法，在ＨＦ，ＭＰ２，ＭＰ３水平下，使用基组６－３１Ｇ，６－３１＋Ｇ对ＳｉＯ的等电子分析ＳｉＸ＾ｍ（Ｘ＝Ｂｅ，Ｂ，Ｃ，Ｎ，Ｆ，Ｎｅ，ｍ＝－４～＋２）进行了几何优化，并计算了相应的平衡几何构型下的振动频率，对ＳｉＯ分子，使用ＱＣＩＳＤ（Ｔ）方法考虑了不同水平下的电相关效应，并考虑了不同其函数６－３１＋Ｇ和６－３１１＋Ｇ的影响。计算结果表明，所有分子的势能曲线都有稳定的极小值，并且键长与频     

配合物La（C5O3H3）3·C12H8N2·H2O的合成和表征

本以α－呋喃甲酸（Ｃ５Ｏ３Ｈ４）和邻菲罗啉（Ｃ１２Ｈ８Ｎ２）为配体,在乙醇８溶剂中与硝酸镧反应,合成了与稀土离子Ｌａ（Ⅲ）的三元混配配合物。经元素分析确定其配合物的组成为Ｌａ（Ｃ５Ｏ３Ｈ３）·Ｃ１２Ｈ８Ｎ２·Ｈ２Ｏ,同时还通过了ＩＲ、＾１ＨＮＭＲ、ＵＶ、ＴＧ－ＤＴＡ等谱光的测试与分析,表征了配合物的组成结构和性质。ＩＲ、＾１ＨＮＭＲ和ＵＶ谱的分析结果表明配体羧酸是以脱质子的酸根形式与中心稀土离子     

双金属团簇Cu12Fe吸附CO和H2的理论研究

基于第一性原理密度泛函理论(DFT)方法研究了Cu₁₂Fe团簇的结构稳定性、热力学稳定性和反应活性.计算得出正二十面体Fe原子核心团簇Ih-core比正二十面体Fe原子壳层团簇Ih-shell的热力学稳定性更强.通过分析吸附能讨论了CO和H₂在Ih-core团簇上的吸附构型.计算结果表明,Ih-core团簇以顶角Corner位吸附CO时吸附能最大,吸附模型最稳定,H₂吸附过程中发生了解离,两个氢原子均形成表面Facet位吸附构型.最后,通过分析前线轨道得到吸附过程的轨道信息.     

氨和甲醇团簇中的质子转移反应

应用激光多光子电离质谱和分子束技术研究和氨和甲醇二元团簇,实现观测到两个系列质子化的团簇离子：（ＣＨ３ＯＨ）ｎＨ＾＋和（ＣＨ３ＯＨ）ｎＮＨ４＾＋（１≤ｎ≤１４）,其产生是经过二元团族内的质子转移反应。同时也研究了氘代甲醇ＣＨ３ＯＤ和氨混合团簇,结果表明ＯＤ原子团中的Ｄ转移概率比ＣＨ３原子团中的质子转移概率大几倍。在ＨＦ／ＳＴＯ－３Ｇ和ＭＰ２／６－３１Ｇ＊＊水平上对氨和甲醇二元团簇进行了计算,结果表明与ＣＨ３相比ＯＨ中的质子转移更加容易,因为ＣＨ３中的质子转移过程中要克服高度约１２０ｋＪ／ｍｏｌ的能垒。     

[Mo3S7]分子簇和聚合簇合物的振动光谱和电子光谱

本文报道了分立簇「Ｍｏ３Ｓ７（ｄｔｐ）３Ｉ」１及它的四聚物｛「Ｍｏ３ＳＵ（ｄｔｐ）３」４Ｉ｝．｛（ＨｇＩ３）４．Ｋ｝２（ｄｔｐ＝Ｓ２Ｐ（ＯＣ２Ｈ５）＾－２的ＩＲ,Ｒａｍａｎ和ＵＶ－Ｖｉｓ光谱,并讨论分立的「Ｍｏ３Ｓ７（ｄｔｐ）３Ｉ」在四聚后这些光谱的变化。     

HCnS^＋和HSCn^＋（n=1～9）结构的ab initio研究

应用量子化学从头计算方法，在ＨＦ／６－３１Ｇ水平上，采用Ｂｅｎｙ优化法，优化了ＨＣｎＳ＾＋和ＨＳＣｎ＾＋（ｎ＝１￣９）两种同分异构簇离子的几何构型，计算了它们的电子总能量、相邻簇离子的能量差及其平均原子结合能。计算结果表明：ＨＣｎＳ＾＋比相应的ＨＳＣｎ＾＋稳定。计算结果还显示，无论是优化后的几何构型，还是各种能量值，均显示出明显的奇偶交替变化的趋势，ｎ为奇数的簇离子比相应的ｎ为偶数的簇离子稳定，这     

Mössbauer studies in a-Fe76-xNixCr4B12Si8

Room temperature Mössbauer studies on a-Fe_76-xNi_xCr₄B₁₂Si₈ alloys (0≤x≤30) are reported. The average hyperfine field is observed to remain constant. P(H) shows a low hyperfine field component which is found to be nearly absent for 2≤x≤4 samples. An attempt has been made to understand the correlation of this to the low temperature resistivity behaviour of Cr containing Fe-based amorphous alloys.     

Eu（C8H7O3）3·C12N2·H2O配合物的合成与表征

合成了新的Eu(C8H7O3)3·C12H8N2·H2O配合物.并经元素分析、摩尔电导、IR、UV、1H NMR等表征,初步确定配体3-甲氧基苯甲酸以桥式双齿形式和Eu(Ⅲ)配位.     

Ba8Si46、Ba8Au6Si40和Ba8Cu6Si40电子特性的研究

布局分析和态密度结果均表明,Ba8Si46　化合物中Ba原子6s轨道上电子一部分向5d轨道转移,另一部分向笼上Si原子3p轨道转移.对于Ba8Au6Si40、Ba8Cu6Si40分析结果表明,由于Cu (Au) 向Si转移部分电子,导致了Cu (Au)-6c与Si-24k原子间成键由共价键趋向离子键.带结构的分析表明三者均为弱金属,其中Ba8Cu6Si40和Ba8Au6Si40的导电能力更强一些.     

Ba8Si46、Ba8Cu6Si40和Ba8Au6Si40电子特性的研究

布居分析和态密度结果均表明,Ba8Si46化合物中Ba原子6s轨道上电子一部分向5d轨道转移,另一部分向笼上Si原子3p轨道转移.对于Ba8Cu6Si40、Ba8Au6Si40分析结果表明,由于Cu(Au)向Si转移部分电子,导致了Cu(Au)-6c与Si-24k原子间成键由共价键趋向离子键.带结构的分析表明三者均为弱金属,其中Ba8Cu6Si40和Ba8Au6Si40的导电能力更强一些.     

Deformation effects in the 28Si+12C and 28Si+28Si reactions

The possible occurrence of highly deformed configurations is investigated in the ⁴⁰Ca and ⁵⁶Ni di-nuclear systems as formed in the ²⁸Si + ¹²C, ²⁸Si reactions by using the properties of emitted light charged particles. Inclusive as well as exclusive data of the heavy fragments and their associated light charged particles have been collected by using the ICARE charged particle multidetector array. The data are analysed by Monte Carlo CASCADE statistical-model calculations using a consistent set of parameters with spin-dependent level densities. Significant deformation effects at high spin are observed as well as an unexpected large ⁸Be cluster emission of a binary nature.     

Mössbauer studies of Ni70Fe10Si8B12 metglass: Reentrant properties

Amorphous metal Fe₁₀Ni₇₀Si₈B₁₂ has been studied by Mössbauer spectroscopy without and with an weak applied field in the plane of ribbons. Reentrant properties have been confirmed with the existence of a canted state at low temperature. Studies with different values of the applied field have shown that a field near 50 0e is sufficient to saturate the average direction of the ferromagnetism.     

TDPAC characterization of Ni2HfF8·12H2O and its decomposition products

The hyperfine interaction in Ni₂HfF₈·12H₂O has been determined between 77 K and 1100 K by means of the time-differential perturbed angular correlation technique. From 200 K on, the one-site phase existing at lower temperatures undergoes a gradual phase transition until, at room temperature, the populations of both phases attain a 2:1 ratio. While the quadrupole frequencies characterizing them exhibit aT ^3/2 thermal dependence, their population ratio seems to obey a Boltzmann distribution. At 350 K, when the η-value of the high temperature phase electric field gradient approaches its maximum value, the starting compound decomposes to NiHfF₆·6H₂O. A kinetics study of the Ni₂HfF₈·12H₂O recovery at room temperature seems to indicate that a tri-dimensional diffusion mechanism is responsible for the corresponding reaction process. The first decomposition product of NiHfF₆·6H₂O left to atmospheric pressure is found to be NiHfF₆·4H₂O at 368 K and, between 414 K and 590 K, the high temperature cubic phase of NiHfF₆ and Hf₂OF₆ can be simultaneously observed. Finally, monoclinic HfO₂ appears from 1020 K on, having been preceded by an interaction which can be though of as depicting a preliminary stage in hafnia formation.     

Metastable states in Si:H

The results of ab initio LDF calculations applied to large clusters of Si atoms containing H in various positions are described. We find the bond centred (BC) defect to be most stable for neutral and positively charged H. H placed at an antibonding site is also stable with an energy 0.1 eV higher than the BC defect. The stability of H₂ and H^*₂ is also discussed. New results are reported for the conversion of BC defects into Si dangling bonds. It is found that H attached to vacancy-like defects is bi-stable: for Si-H-Si lengths less than ≈3.8 Å, the BC defect is stable, whereas for longer separations, the Si-H ··· Si dangling bond is stable. A discussion of the relevance of this to the Staebler-Wronski effect is given.