油酸钠浮选高岭石的溶液化学机理研究

通过单矿物浮选实验、浮选溶液化学计算、Zeta电位测试和红外光谱分析研究了油酸钠对高岭石浮选行为的影响以及溶液化学作用机理,旨在为阴离子捕收剂高效浮选高岭石以及铝土矿正浮选提供理论指导.通过高岭石溶解组分的浓度对数图(lg c-pH)理论推算出高岭石零电点PZC=4.52,较Zeta电位所测值(PZC=3.9)偏高,与文献利用AFM所测的高岭石PZC=4～5一致.通过油酸钠溶液各组分的浓度对数图(lg c-pH)可知,形成最大浓度离子-分子缔合物的pH值为8.44,其与最佳浮选pH一致,此时高岭石表面Zeta电位负移也最显著,说明离子-分子缔合物的浮选活性最大.加入阴离子捕收剂油酸钠后高岭石表面Zeta电位整体向负移,说明油酸钠通过非静电力吸附在高岭石表面.结合红外光谱测试结果推断油酸钠与高岭石可能发生化学吸附.     

立方相WO_3电子结构及其(001)活性表面吸附性能

采用基于密度泛函理论的第一性原理方法探讨了WO3的电子结构和表面性能,进行了能带结构、态密度和有效电子质量的模拟计算,对WO3吸附12种原子后的吸附体系进行了理论分析。结果表明,WO3价带顶主要是由O的2p态电子构成,导带底主要是由W的5d态电子构成。当价带顶上的O-2p电子吸收能量后可跃迁至导带底的W的5d轨道上,同时在O-2p上产生空穴。其电子迁移率为1.35,表明其电子-空穴的分离率较高,光催化活性较强。探讨了WO3的(001)洁净表面对12种非金属原子的吸附情况,WO3吸附F原子后表面能最小。     

MgO（111）弛豫表面氢的吸附问题研究

针对氢在MgO(111)表面的吸附问题,结合基于密度泛函理论的第一性原理方法,对氢在MgO(111)表面的势能面和4种可能吸附位置及2种不同吸附方式的能量进行了计算,并对吸附H原子过程中的电荷转移情况进行了研究.研究表明,H2分子在MgO(111)表面垂直吸附时均为物理吸附,最优吸附位置为fcc,而平行吸附时均为化学吸附;H原子在Mgo(111)表面的hcp和on-top吸附位置处的吸附能相差不超过0.1 eV;电荷密度计算观察到吸附H原子后,与H原子最近邻的Mg原子表面发生了电荷转移.     

Al在Si（111）面上吸附的ASED—MO研究

本文使用分子簇模型和原子交迭和电子离域-分子轨道(ASED—MO)方法,计算Al吸附在Si(111)面上不同位置的键长和键能(吸附能)。按照总能量最小原则,对铝吸附在硅表面层的顶位、中心位、再构中心位、迭位、再构迭位和桥位的不同位置,分别计称出Al—Si的键长为2.38、2.55、2.71、2.68、2.61和2.49×10~(-10)m;各位置对应的吸附能分别为0.72、0.37、0.40、0.01、1.02和0.62eV。另一方面,根据Al_3Si_(26)H_(26)分子簇的计算结果,得出3个铝原子吸附在Si(111)面上的最佳位置为相邻的双折(桥位)位置,同时由能量计算表明铝的复盖率为3/7单原子层。     

CO在Cu表面吸附过程中电荷转移的理论研究

应用密度泛函理论．对CO分子在Cu(100)表面的吸附过程进行了研究。计算了CO分子以垂直方式在3种不同吸附位置吸附时CO分子和Cu(100)表面原子的电荷分布。结果表明：与碳原子最近邻的铜原子表面上发生明显电荷转移．而其他表面原子及体相原子的电子结构没有变化。Mulliken集居数及局域态密度分析表明，吸附过程中CO分子与表面Cu原子相互作用主要是CO分子内杂化轨道和3d，4s，4p(Cu)的贡献。     

纤锌矿AlN中反位和间隙点缺陷电子结构的最大局域化Wannier函数方法研究

结合第一性原理计算方法,利用最大局域化Wannier函数方法研究了纤锌矿AlN中反位和间隙点缺陷引起的电子结构变化及成键性质.研究发现:在N反位缺陷结构中,反位N原子只与[0001]方向上最近邻的N原子成键,未成键的孤对电子局域在反位N原子及其余最近邻的3个N原子附近;在Al反位缺陷中,反位Al原子与垂直于[0001]方向的底面上3个最近邻Al原子成键.研究同时发现:在反位和间隙缺陷中,N间隙对电子结构影响最小,间隙N原子与下方最近邻的3个Al原子成键;尽管Al间隙对电子结构影响最大,但间隙Al原子并不与周围原子成键.无疑,相比于传统的电子结构分析方法,最大局域化Wannier函数方法更加直观便捷,能给出清晰的物理图景.     

改性石墨烯纳米材料气敏特性的理论研究

利用基于密度泛函理论的第一性原理计算方法,研究单个CO和O2气体分子在多种金属原子修饰的石墨烯表面的吸附作用.结果表明,空位缺陷结构的石墨烯能够显著提高金属原子的稳定性,失去部分电荷的金属原子有助于调控气体分子的吸附特性.对比发现,单个金属Al和Mo原子掺杂的石墨烯体系对O2分子具有极高的灵敏性和选择性.通过不同气体分子的吸附能够调控石墨烯体系的电子结构和磁性.研究结果测试了不同金属原子修饰石墨烯表面的反应活性,为设计新型金属-石墨烯功能器件提供参考.     

CO在Cu表面吸附过程中电荷转移的理论研究

应用密度泛函理论,对CO分子在Cu(100)表面的吸附过程进行了研究。计算了CO分子以垂直方式在3种不同吸附位置吸附时CO分子和Cu(100)表面原子的电荷分布。结果表明:与碳原子最近邻的铜原子表面上发生明显电荷转移,而其他表面原子及体相原子的电子结构没有变化。Mulliken集居数及局域态密度分析表明,吸附过程中CO分子与表面Cu原子相互作用主要是CO分子内杂化轨道和3d,4s,4p(Cu)的贡献。     

Y分子筛中硅铝桥羟基结构调变规律的理论研究

Y分子筛中B酸的酸性在催化过程中起着主要作用,其结构的变化反应了B酸的强弱。采用周期性模型模拟了HY、[AlO]+/HY及 [Al(OH)]2+/HY中B酸位置的稳定结构,从第一性原理和分子动力学两方面研究了B酸中心的结构变化与周围微环境的关系。通过几何结构、电子结构和分子力学统计结果发现,非骨架铝物种的加入增加了B酸的强度,且与H原子在12元环上的分布数量有关系,H原子越少,其酸性越强。B酸中心H原子与O原子结合能力越弱,并且H原子失去电子越多,B酸酸性越强。非骨架铝的加入能增强B酸的酸性,且[Al(OH)]2+非骨架铝物种对B酸性质的影响明显。研究可为分子筛B酸调变提供理论支持。     

谈物质结构研究的当代进展

300年前,英国科学家R·玻意耳提出化学无素的概念;100多年前,人们从化学实验中知道,物质是由分子组成的,分子是由原子组成的。近百年来,在科学实验的基础上,物理学家发现了电子、质子和原子核并逐步形成了原子模型,认识到原子是由原子核与核外运动的电子所组成。 原子核结构是一个远较原子构结复杂的研究领域。本世纪30年代,科学家们陆续发现了中子、正电子。后来在宇宙射线中又发现了μ子、π介子和奇异粒子。50年代以后,通过高能加速器又发现了几百种新粒子,它们大多数在自然界中不存在,只能在高能实验室里产生出来。     

Reactivity of Tourmaline by Quantum Chemical Calculations

ZnAb initio calculations on reactivity of tourmaline were performed using both Gaussian and density function theory discrete variation method （DFT-DVM）. The HF, B3LYP methods and basis sets STO-3G（3d,3p）,6-31G（3d,3p） and 6-311＋＋G（3df,3pd） were used in the calculations. The experimental results show energy value obtained from B3LYP and 6-31＋＋1G（3df,3pd） basis sets is more accurate than those from other methods. The highest occupied molecular orbital （HOMO） of the tourmaline cluster mainly consists of O atom of hydroxyl group with relative higher energy level, suggesting that chemical bond between those of electron acceptor and this site may readily form, indicating the higher reactivity of hydroxyl group. The lowest unoccupied molecular orbital （LUMO） of the tourmaline cluster are dominantly composed of Si, O of tetrahedron and Na with relative lower energy level, suggesting that these atoms may tend to form chemical bond with those of electron donor. The results also prove that the O atoms of the tourmaline cluster have stronger reactivity than other atoms.     

Orbital Calculations of Kaolinite Surface:on Substitution of Al~(3 ) for Si~(4 ) in the Tetrahedral Sites

The surface properties of kaolinite were determined using density functional theory discrete variational method(DFT-DVM)and Gaussian 03 program.A SiO_4 tetrahedral hexagonal ring with two Al octahedra was chosen to model the kaolinite crystal.The total density of states of the kaolinite cluster are located near the Fermi level at both sides of the Fermi level.Both the highest occupied molecular orbit (HOMO)and the lowest unoccupied molecular orbit(LUMO)of kaolinite indicate that kaolinite system can not only readily interact with electron-acceptor species,but also readily interact with electron-donor species on the edge surface and the gibbsite layer surface,and thus,shows amphoteric behavior.Substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site linking the vacant Al~(3 ) octahedra does not increase the surface chemical reactivity of kaolinite,while substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site with the apex O linking Al~(3 ) octahedra increase the surface chemical reactivity of the siloxane surface of kaolinite,especially acting as electron donors. Additionally,substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site results in the re-balance of charges,leading to the increase of negative charge of the coordinated O atoms of the AlO_4 tetrahedra,and therefore favoring the formation of ionic bonds between cations and the surface O atoms in the basal plane.     

Chemial Bond and Stability of Adsorption of [Au(AsS_3)]~(2-)on the Surface of Kaolinite

1　IntroductionKaoliniteisoneofthemostwide spreadphyllosili catesintheearthcrust.Thegoldiscloselyrelatedtoclayinmanysubmicrometergoldminerals .Itisimportanttostudytheinterrelationbetweengoldandclayforunder standingthecloseassociationofgoldandclaymineralsa…     

Orbital Calculations of Kaolinite Surface： on Substitution of Al^3＋ for Si^4＋ in the Tetrahedral Sites

The surface properties of kaolinite were determined using density functional theory discrete variational method （DFT-DVM） and Gaussian 03 program. A SiO4 tetrahedral hexagonal ring with two A1 octahedra was chosen to model the kaolinite crystal. The total density of states of the kaolinite cluster are located near the Fermi level at both sides of the Fermi level. Both the highest occupied molecular orbit （HOMO） and the lowest unoccupied molecular orbit （LUMO） of kaolinite indicate that kaolinite system can not only readily interact with electron-acceptor species, but also readily interact with electron-donor species on the edge surface and the gibbsite layer surface, and thus, shows amphoteric behavior. Substitution of Al3^＋ for Si4＋ in the tetrahedral site linking the vacant Al3^＋ octahedra does not increase the surface chemical reactivity of kaolinite, while substitution of Al3^＋ for Si^4＋ in the tetrahedral site with the apex O linking Al3^＋ octahedra increase the surface chemical reactivity of the siloxane surface of kaolinite, especially acting as electron donors. Additionally, substitution of Al3^＋. for Si^4＋ in the tetrahedral site results in the re-balance of charges, leading to the increase of negative charge of the coordinated O atoms of the AlO4 tetrahedra, and therefore favoring the formation of ionic bonds between cations and the surface O atoms in the basal plane.     

Quantum Chemistry Calculations on the Interaction Between Kaolinite and Gold

The density function and discrete variation method ( DFT - DVM) is used to study the interaction between kaolinite and gold. The correlation among the structure, chemical bond and stability is discussed. Several models are selected without gold and with gold in different directions and sites . The results show that the models with gold on the edge of kaolinite basal layer are more stable than those with gold above or under the layer, the models ivith gold near to [ A1O2 ( OH)4 ] octahedra are more stable than those with gold near to the vacancy without aluminium. The interaction between gold and the surface ions of kaolinite is strong enough to form the surface complexes.     

Chemial Bond and Stability of Adsorption of [Au（ AsS3 ）]^2- on the Surface of Kaolinite

Density function theory and discrete variation method (DFT-DVM) were used to study the adsorption of [Au( AsS3 )]^2- on the surface of kaolinite. The correlation among structure, chemical bond and stability was discussed. Several models were selected with [ Au( AsS3)]^2- in different directions and sites. The results show that the models with gold on the edge of kaolinite basal layer contain pincerlike bond among gold and several oxygen atoms and form strong Au - 0 covalent bond, so these models are more stable than those with gold above or under the layer. The models with gold near to [ AlO2(OH)4] octahedra are more stable than those with gold near to the vacancy withont aluminium. These two stable tendencies in kaolinite- [ Au( AsS3)]^2- are stronger than that in kaolinite-Au systems. The interaction between [ Au( AsS3 )]^2- and kaolinite is stronger than that between gold and kaolinite, and this interaction is strong enough to form the surface complexes.     

Reaction Activity of Kaolinite Surfaces：Quantum Chemistry Calculations

The anion-kaolinite surface infractions and AuS - adsorption onto the surfaces of kaolinite were studied using the self-consistent-field discrete variation ( SCF - Xα - DV) method. Electronic structure and energies of the system of anion AuS- adsorbed on an atomic cluster of kaolinite were calculated. The results show that the systems with lower total energy are those AuS- adsorbed on the edge surfaces, which indicates that the systems of adsorption of AuS- on the edges are more stable relative to those adsorbed on the basal plane. On the other hand, bond order data suggest that significant shifting of atomic charge and the overlapping of electronic cloud between Au ( Ⅰ ) of the AuS- and the surface ions of kaolinite would take place in the systems with AuS - being adsorbed on the edges, especially at the she near A1 octahedra. Therqrore, it can be concluded that edge sites will dominate the complexation reactions of the surfaces of kaolinite, with negligible contributions from other fimctional groups on the basal plane, which are dominated by either siloxane sites in silica layers or aluminol sites in gibbsite layers.     

脂肽类抗真菌物质的理论化学研究

用量子化学半经验计算方法对3种脂肽类抗真菌物质,棘念珠菌素B,西咯芬净和LY303366进行量子化学计算,优化其构型,得到了电子结构和电荷分布。讨论它们的抗真菌活性差异的结构因素,认为抗真菌活性部位与LUMO的成份以及其提供的空轨道的亲电能力有关,空轨道亲电能力越强,抗真菌能力就越强。推测出抗真菌反应是棘念珠菌素的亲电反应,活性部位是位于脂肽环的侧链,而不是在脂肽环本身。侧链的化学结构对脂肽类抗真菌物质分子的电子结构产生重大影响。解释了3种脂肽类抗真菌物质活性强弱的顺序。     

Interface Characteristics Between Colloidal Gold and Kaolinite Surface by XPS

The distribution of gold colloids in kaolinite and the interaction between gold and kaolinite surface were investigated by transmission electron mieroscotgy （TEM） and X-ray photoelectron spectroscopy （ XPS ）. There is strong interaction between the gold particles and the edge surfaces of kaolinite, in low pH solution, the edge surface of kaolinite is positively charged and electrostutic attrcactive force between colloide gold panicles and the positive edge surface of kaolinite woald facilitate the adsorption of colloidal gold particles onto the suface. TEM observation shows that the aggregate morphology of gold particles was dominated by particle-particle interaction and gold particles were adsorbed on the edge surface of kaolinite crystals , resulting from the electrostatic attractive force between colloidal gold particles and the positice surfaces of kaolinite. XPS data show that in Au4 f electron spectra there are four energy peaks related to gold, 83.8 eV, 85.7 eV, 87.5 eV, and 89.4 eV, respectively, which suggests that in chemical states there are metallic gold and Au bonded to O, similar to the form of Au2O3 , and composite Au2O3 is formed between the edge surface of kaolinite and colloidal gold surface.     

计算机辅助化学教学研究

采用计算机三维动画和多媒体技术对大学基础化学物质结构基础知识进行了立体化教学研究 ,内容包括原子结构、分子结构、晶体结构、分子和晶体的对称性、化学键理论物理模型、分子间的相互作用力以及结构化学的一些基本概念和基础知识。并且还介绍了所研制软件的基本特点和教学效果。