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1.
More than one hundred models were designed to reflect the local structure and electronic property of Ni-Fe amorphous alloys. After calculating by DFF method, a series of configurations of clusters NixFe and NiFex (x = 1 - 5) were gained. The configurations, which possessed the lowest energies and non-imaginary frequencies, were considered the most stable optimized structures. The catalytic activity, charge and magnetic properties were analyzed and discussed. The different Fe content changed the catalytic properties of clusters through altering the value of Fermi level of every cluster. However the density of state (DOS) nearby Fermi level and average 3d orbital population of atom Ni, which were also important properties related to the catalytic activation, were little changed. Based on the Fermi level, the activity of catalyst toward hydrogenation reaction would be considered best when the ratio of Ni to Fe was close to 1. The Fermi level of clusters was far distant to the level of nitrogen in singlet state. It would be the reason why the reaction condition in ammonia synthesis and nitrogen fixation process was rigorous. When Fe atom contents were higher than 75% (NiFe3), the electrons transferred from atom Fe to Ni, but when the ratio was decreased, the transfer was reversed. The ratio of atoms of local structure also played an important role in the aspect of electron transition. On the average 3d orbital population of atom Fe, the average magnetic moments of Fe atoms in clusters were calculated. When Fe atom contents were 50% nearly, the average magnetic moment achieved the highest point. 相似文献
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The enhanced magnetic and photocatalytic properties of(Fe, Ni)-codoped SrTiO_3 with and without oxygen vacancies are investigated using the first-principles calculations based on the density functional theory plus U calculations. It is revealed that the structure phase transition associated with O vacancy imposes significant influence on magnetic and optical properties. The results show that the Ni oxidation state in(Fe, Ni)-codoped SrTiO_3 is about 2~+, which is different from that of 4~+ in Ni monodoped SrTiO_3 in previous experimental investigations. The presence of O vacancy leads to a semiconductor-half-metal transition in codoped SrTiO_3. The(Fe, Ni)-codoped SrTiO_3 without O vacancy produces an enhanced magnetization and induces a giant magnetic moment of 3 μB, while a relatively small magnetic moment of 0.36 μB is generated in(Fe, Ni)-codoped SrTiO_3 with O vacancy. The origin of the large enhancement of magnetic moment in(Fe, Ni)-codoped SrTiO_3 without O vacancy was ascribed to the reduced hybridization in Fe–O bonds and the enhanced hybridization in Ni–O bonds, which modulated antiferromagnetic spin structure. The dispersion of the conduction bands and valence bands of codoped SrTiO_3 is enhanced after codoping, which benefits the photocatalytic performance. Furthermore, the(Fe, Ni)-codoped SrTiO_3 shows a remarkable red-shift of absorption spectra edge and induces a strong optical absorption in the visible light region, indicating that it could be taken as a potential candidate for photocatalytic materials. 相似文献
3.
A novel synthetic strategy was developed to prepare polyphosphazenes containing C60 moieties. Thus, the phosphonitrile chloride trimer underwent thermal ring-opening polymerization (ROP) in the presence of C60 molecules to yield the reactive macromolecular intermediate, C60-containing poly(dichlorophosphazene). And then, the other groups could be linked to the phosphazene backbone by nucleophilic substitution reaction of the chlorine atoms in this intermediate to produce a series of C60-containing polyphosphazene. The polymer exhibits good solubility in common organic solvents and is thermally stable. 相似文献
4.
Jun-ying Weng Ting-ting Zhou Ying-hui Zhang 《化学物理学报(中文版)》2014,(3):285-290
Theoretical study on the supramolecular complexes formed between boron-doped het- erofullerene (C59B) and zinc porphine (ZnF), namely C59B-ZnP and its anion species C59B-ZnP, was performed by density functional theory calculation at wB97XD/6-31G(d) level. Strong interaction between porphyrin and heterofullerene moiety was predicted for these complexes based on geometry and electronic structure analysis. Especially, pseudobonding interaction occurring between the B atom of fullerene and the N atom of porphyrin was predicted to occur in C59B-ZnP complex, but be broken in C59B-ZnP complex. Time-dependent density functional theory calculation manifests the redshift of electron absorption for ZnP upon the interaction with heterofullerene. 相似文献
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Hydrogen is known to play a negative role in mechanical properties of steel due to hydrogen embrittlement. Surface strain modifies the surface reactivity. In this paper, we employed spin-polarized periodic density functional to study the atomic H adsorption and diffusion on the biaxial strained Fe(110) surface. The result shows that the adsorption of H at the Tf site is the most stable on compressive surface and tensile surface. And H atom on the top site relaxes to Tf site on the strained surface. The adsorbed hydrogen atom at all calculated adsorption sites relaxes towards the surface due to the tensile strain. Lattice compression makes the bonding strength weaker between H atom and the surface. The analysis of the partial density of states shows that H 1 s orbital hybridizes with the Fe 4 s orbital. The result of charge density difference shows electrons are transferred from Fe to H atom. Compressive strain reduces the transferred electrons and decreases the Mulliken electrons of Fe 4 s orbital, which weaken the bonding interaction between H and Fe atoms. H atom diffuses into subsurface through a distorted tetrahedron. Surface strain does not change diffusion path but affects the diffusion barrier energy. Tetrahedron gap volume in the transition state of compressive system decreases to increase the diffusion barrier. This suggests compressive strain impedes H penetrating into the Fe subsurface. The present results indicate that it is a way to control adsorption and diffusion of hydrogen on the Fe surface by surface strain. 相似文献
6.
The combination energy and chemical adsorption energy of N-substituted perfluoropoly-alkyletherphenylamide (PFPEA) additive to perfluoropolyalkylether oxygen radical (RfO.) and to Fe atom have been calculated by quantum chemical methods. Structural characteristics, action mechanism, property of donating-accepting electron and substituent effect for antioxidant and anticorrosive additive are investigated. It is found that HOMO of the additives is a π-molecular orbital with lone pair electron of heteroatom. The HOMO of PFPEA additive reacts with LUMO of Fe atom to result in chemical adsorption. The LUMO of additive can interact with the SOMO of RfO. and accept electron of RfO. to form stable addition product. The additives have the property of donating-accepting electron. The electron-releasing group, particularly, the phenyl group, introduced to N atom of phenylamide can increase the combination energy and chemical adsorption energy, and enhance the antioxidant and anticorrosive efficiency. The research achi 相似文献
7.
The molecular geometries and electronic structures of the fullerene derivatives C36(OH)n(n = 1~2) have been investigated on the basis of density functional theory calculation at the B3LYP/6-31++G* level.The geometry optimization results indicate that the location of C2 atom is the most active site in the three potential adding patterns,and the C1 or C2 site has a larger binding energy than C3 for the addition reactions of C36(D6h) cage and OH radicals resulting from the larger curvature.The electronic structure calculation results disclose that the C2 site has larger electronic population in HOMO and larger spin density,and the addition reaction on the C2 site need overcome a lesser energy gap than that on the C1 or C3 site.Thus,the addition is controlled jointly by the curvature and the electronic factors.Besides,when two hydroxyls are added to the C36 surface,the C2 sites are also the most active locations.The most stable addition adduct of C36(OH)2 is the isomer which holds Ci symmetry,and the spin multiplicity seriously affects the stabilities of the adducts. 相似文献
8.
《中国化学快报》1992,(6)
The frontier orbitals HOMO and LUMO of the fullerene C_(60) hasbeen given in a system of 60 motion-coordinates, of which each origin is ateach C atom of fullerene C_(60) and each z-axis is in the directionperpendicular to C_(60)'S spherical surface. In this motion-coordinate systemthe HOMO and LUMO of fullerene C_(60) obviously display characteristics ofspherical n-molecular orbitals π_n. The Fenske-Hall quantum-chemical methodis used in calculation for the electronic structure of the fullerene C_(60). 相似文献
9.
Two types of polysiloxanes,which contain both C60 moieties and carbazolyl groups in the side chains with a difference in the numbers of the reacting site on C60 molecules,were synthesized and their fluorescent properties were studied to distinguish the role of C60 in the luminescent polymers.Our results demonstrated that when C60 moieties are bonded to the polymers as multisubstituents but not linked to the luminescent moieties directly,the luminescence of the resultant polymers were still very strong instead of quenching,even the substituted degree is only 1.01. 相似文献
10.
In the ethyl-cyanoethylcellulose ((E-CE)C)/dichloroacetic acid (DCA) cholesteric liquid crystalline solution, the hand-like texture is formed when the mesophase aggregates with the disk-like texture grow to big enough and merge with each other with increasing concentration. The band-like texture is composed of parallel equidistant bright and dark alternative strips which are about 0.2-2.0 μm in width. In the band-like texture, the layers of ordered polymer chains are perpendicular to the solution film and the axes of helicoids are parallel to it. The width of the strips is different in different zones. Under the effect of an external magnetic field, the strips in the band-like texture first become wider and then narrower gradually.Moreover, the axes of helicoids in the (E-CE) C/DCA mesomorphic solution change from the direction normal to the magnetic field to the agreement with the magnetic field direction. 相似文献
11.
Toshihiko Osaki Tomoki Hamada Yutaka Tai 《Reaction Kinetics and Catalysis Letters》2003,78(2):217-223
The catalytic hydrogenation of C60 on Ru, Rh and Ir produced C60H18 mainly, while Pd, Pt, Co and Ni catalysts gave C60H36 principally. Very little activity was observed on Au and Fe. The higher hydrogenated fullerene obtained on Pd, Pt, Co and
Ni was ascribed to the smaller % d-character of the metallic bond, on which the fullerene and hydrogen may more strongly be
adsorbed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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在高分子领域中,C60的高分子化一直是C60材料化的一个重要途径.迄今为止,制备含C60高分子的方法有以下几种:(1)采用自由基引发剂、阴离子引发剂或阳离子引发剂引发C60与烯类单体共聚[1,2];(2)对C60进行表面修饰,引入可聚合官能团,合成含C60的单体,随后聚合成含C60的高分子[3];(3)制备出带有功能基团的高分子前体,再通过功能化反应将C60引入高分子链[4~9]. 相似文献
14.
以C60晶体中分子两种取向排列形成的双能级系统为基础,通过探讨C60晶体在有序相的热力学性质,得到了38o和98o两种取向排列的分子在晶体中均匀分布的结构稳定性结论.根据已报道的C60晶体在有序相两端点温度85 K 和260 K取向分布的实验结果,将较高的分子取向(38o)能级的概率转化成分数值1/6和3/8,得到了有序相两种取向分子在两温度端点的分布规律.当概率的分数值为1/4和1/3时,C60晶体将具有较大的结构稳定性和较小的介电损耗及内耗值,对应的温度分别为122.6和194.3 K.因而解释了介电实验结果出现异常的现象是由38o取向分子均匀分布的"规则-无规-规则"变化所造成的. 相似文献
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水溶性C60衍生物的电化学合成及表征 总被引:1,自引:1,他引:0
通过电化学方法合成了一种具有良好水溶性并能在水及空气中长期稳定存在的C60衍生物,经电泳实验证实该衍生物带负电荷。红外光谱及近红外光谱显示该水溶物有稳定键合的CO和OH基,所以表现出强亲水性。在可见区(从420nm到700nm)有非常宽的发光谱带,这是由于Jahn-Teller效应以及C60和OH基之间的相互作用引起的。 相似文献
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本文综述了C60丙环桥式衍生物的种类,制备方法及研究进展,并介绍部分相关反应机理。 相似文献
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含能富勒烯吡咯烷衍生物的合成及工艺研究 总被引:2,自引:0,他引:2
利用Prato反应合成分离出了新型含硝基富勒烯吡咯烷衍生物1, 并对其工艺条件进行了研究, 探讨了反应物计量比、温度及时间对产物1产率的影响, 得到了合成产物1的最佳工艺条件: C60, 间硝基苯甲醛和N-甲基甘氨酸的物质的量比为1∶1∶2, 温度为100 ℃, 反应时间为16 h, 此时产物1产率达到94.8%(以消耗的C60计). 同时用UV-Vis, FT-IR, 1H NMR, 13C NMR and MS spectra等光谱手段确定了产物1的分子结构. 相似文献