ZnF2:Ni2+晶体局域结构的理论研究

从光谱和EPR数据出发,用完全对角化方法确定了ZnF:Ni 晶体中的23(4 515 键长与键角,证实了 ZnF:Ni晶体的局域结构畸变的存在%研究结果表明,ZnF:Ni晶体与/01( 基晶的结构参数对比,发现掺杂23(4 离子的ZnF:Ni晶体分别产生了沿. 轴的伸长畸变和在,平面的压缩畸变.光谱和,-.参量计算的理论值与实验值非常接近.     

ZnF2：Ni^2＋晶体局域结构的理论研究

从光谱和EPR数据出发,用完全对角化方法确定了ZnF2：Ni^2＋晶体中的Ni^2＋-F^-键长与键角,证实了ZnF2：Ni^2＋晶体的局域结构畸变的存在.研究结果表明：ZnF2：Ni^2＋晶体与ZnF2基晶的结构参数对比,发现掺杂Ni^2＋离子的ZnF2晶体分别产生了沿C2轴的伸长畸变和在xy平面的压缩畸变;光谱和EPR参量计算的理论值与实验值非常接近.     

用光谱和EPR谱确定CsMgCl3:Ni2+和CsCdCl3:Ni2+的局域结构

采用半自洽场（semi-SCF）自由Ni^2＋的3d轨道波函数、点电荷-偶极子模型和Ni^2＋-6X-（X=F,Cl,Br,I）络合物的μ-κ-α模型,建立了结构参数与光谱、EPR谱之间的定量关系,利用完全对角化方法,由光谱和电子顺磁共振（EPR）谱,确定了CsMgCl3：Ni^2＋和CsCdCl3：Ni^2＋晶体在77K温度时的Ni^2＋占位和局域结构参数,统一解释了CsMgCl3：Ni^2＋和CsCdCl3：Ni^2＋晶体的结构、光谱和EPR谱.此外,还讨论了高阶微扰方法、参量拟合方法等问题.所得理论结果与实验值符合得很好.     

α-LiIO3∶Ni2+晶体中的Ni2+-VLi三角中心局域结构的研究

通过计算α LiIO3∶Ni2 晶体零场分裂D和 g因子 ,研究了掺杂Ni2 的α LiIO3晶体中Ni2 VLi三角中心的局域结构 ,估算出Ni2 离子应向Li 空位 (VLi)位移ΔZ≈ 0 .2 5 ,以及VLi附近的氧离子应位移ΔX≈ 0 .14 9 .     

LiTaO3：Fe^3＋（Mn^2＋）的EPR参量D与局域结构的研究

用晶体场理论研究了ＬｉＴａＯ３：Ｆｅ＾３＋（Ｍｎ＾２＋）的ＥＰＲ参量Ｄ和掺杂晶体局域结构间的内在联系,计算值与实验值符合较好。结果表明,ＬｉＴａＯ３：Ｍｎ＾２＋局域结构的畸变程度大于ＬｉＴａＯ３：Ｆｅ＾３＋。     

K2MgF4∶Mn2+体系局域结构的理论研究

采用对角化四角晶体场中d5组态离子的完全能量矩阵的方法,研究了K2MgF4∶Mn2 体系的EPR谱与局域晶格结构间的关系,通过拟和EPR谱的低对称参量b02,b04的实验值计算给出了过渡金属Mn2 离子在K2MgF4∶Mn2 体系中局域结构参量R1=0.203 82 nm,R2=0.205 58 nm,以及晶格畸变量ΔR1=0.004 75 nm,ΔR2=0.007 08 nm.     

AlF3:Fe3+系统局域晶体结构理论的研究

本文通过对角化d5电子组态的能量矩阵,同时模拟二阶和四阶EPR参量D和（a-F）,发现Fe3+在AlF3:Fe3+系统有一个膨胀的畸变。这个膨胀的畸变可能是由于Fe3+离子半径大于Al3+离子半径,当Fe3+取代Al3+离子时, Fe3+离子将会推动氟配体向外移动.     

KNiF3晶体的局部结构、吸收光谱和顺磁g因子的统一解释

利用完全对角化方法和强场耦合方案,采用半自洽场（semi-SCF）自由Ni^2＋的d轨道模型和Ni^2＋-6X-（X=F,Cl,Br,I）络合物的μ-κ-α模型研究,建立了含有过渡族金属离子的晶体的局域结构与吸收光谱和顺磁g因子之间的定量关系,对KNiF3晶体的局域结构、吸收光谱和顺磁g因子作出了统一解释,预测了KNiF3晶体的光谱精细结构和零场分裂（ZFS）参量D.所得理论计算结果与实验值符合.     

LiTaO_3:Fe~(3 )(Mn~(2 ))的EPR参量D与局域结构的研究

用晶体场理论研究了LiTaO3:Fe3 (Mn2 )的EPR参量D和掺杂晶体局域结构间的内在联系 .计算值与实验值符合较好 .结果表明 ,LiTaO3:Mn2 局域结构的畸变程度大于LiTaO3:Fe3 .     

Al2O3：Ni^2＋晶体的局域结构研究

应用配位场理论、微扰理论以及叠加模型，建立了零场分裂(Zero-Field Splitting)参量D与Al2O3：Ni^2 晶体局域结构之间的关系式，并通过计算零场分裂参量D值，发现掺Ni^2 离子的Al2O3晶体上、下三棱锥分别产生了沿C3轴的压缩畸变和伸长畸变，零场分裂参量计算结果与实验符合．     

用光谱和零场分裂确定晶体K2ZnF4:Ni2+的局部结构参数

采用半自洽场(semi-SCF)d-轨道模型和点电荷-偶极子模型,利用完全对角化方法,由K2ZnF4:Ni2 的d-d跃迁光谱和零场分裂D,确定了晶体K2ZnF4:Ni2 在常温(290 K)和低温(4.2 K)下的局部结构参数,并预测了顺磁g因子的大小.建立了局部结构参数与光谱、零场分裂之间的定量关系,并统一解释了K2ZnF4:Ni2 晶体的光谱和零场分裂的实验值,所得理论结果与实验值符合得很好.     

四角晶场中K2ZnF4：Ni^2＋的零场分裂D

根据杂质离子可能引起晶体中杂质周围局部结构的畸变，本文计算了晶体Ｋ２ＺｎＦ４：Ｎｉ２＋的零场分裂参量Ｄ，并预言了低温下（４．２Ｋ）晶体结构的畸变     

Crystal structure of the CorA Mg2+ transporter

The magnesium ion, Mg2+, is essential for myriad biochemical processes and remains the only major biological ion whose transport mechanisms remain unknown. The CorA family of magnesium transporters is the primary Mg2+ uptake system of most prokaryotes and a functional homologue of the eukaryotic mitochondrial magnesium transporter. Here we determine crystal structures of the full-length Thermotoga maritima CorA in an apparent closed state and its isolated cytoplasmic domain at 3.9 A and 1.85 A resolution, respectively. The transporter is a funnel-shaped homopentamer with two transmembrane helices per monomer. The channel is formed by an inner group of five helices and putatively gated by bulky hydrophobic residues. The large cytoplasmic domain forms a funnel whose wide mouth points into the cell and whose walls are formed by five long helices that are extensions of the transmembrane helices. The cytoplasmic neck of the pore is surrounded, on the outside of the funnel, by a ring of highly conserved positively charged residues. Two negatively charged helices in the cytoplasmic domain extend back towards the membrane on the outside of the funnel and abut the ring of positive charge. An apparent Mg2+ ion was bound between monomers at a conserved site in the cytoplasmic domain, suggesting a mechanism to link gating of the pore to the intracellular concentration of Mg2+.     

Crystal structure of the MgtE Mg2+ transporter

The magnesium ion Mg2+ is a vital element involved in numerous physiological processes. Mg2+ has the largest hydrated radius among all cations, whereas its ionic radius is the smallest. It remains obscure how Mg2+ transporters selectively recognize and dehydrate the large, fully hydrated Mg2+ cation for transport. Recently the crystal structures of the CorA Mg2+ transporter were reported. The MgtE family of Mg2+ transporters is ubiquitously distributed in all phylogenetic domains, and human homologues have been functionally characterized and suggested to be involved in magnesium homeostasis. However, the MgtE transporters have not been thoroughly characterized. Here we determine the crystal structures of the full-length Thermus thermophilus MgtE at 3.5 A resolution, and of the cytosolic domain in the presence and absence of Mg2+ at 2.3 A and 3.9 A resolutions, respectively. The transporter adopts a homodimeric architecture, consisting of the carboxy-terminal five transmembrane domains and the amino-terminal cytosolic domains, which are composed of the superhelical N domain and tandemly repeated cystathionine-beta-synthase domains. A solvent-accessible pore nearly traverses the transmembrane domains, with one potential Mg2+ bound to the conserved Asp 432 within the pore. The transmembrane (TM)5 helices from both subunits close the pore through interactions with the 'connecting helices', which connect the cystathionine-beta-synthase and transmembrane domains. Four putative Mg2+ ions are bound at the interface between the connecting helices and the other domains, and this may lock the closed conformation of the pore. A structural comparison of the two states of the cytosolic domains showed the Mg2+-dependent movement of the connecting helices, which might reorganize the transmembrane helices to open the pore. These findings suggest a homeostasis mechanism, in which Mg2+ bound between cytosolic domains regulates Mg2+ flux by sensing the intracellular Mg2+ concentration. Whether this presumed regulation controls gating of an ion channel or opening of a secondary active transporter remains to be determined.     

理论分析振动态H2+偶次谐波的辐射机制

理论研究和认证了振动态H_2~+偶次谐波的辐射机制.结果表明,偶次谐波是由于谐波辐射在激光上升和下降区间的不对称效应所产生的.具体来说,在低振动态下,偶次谐波主要来源于激光下降区间.随着振动态增大,来源于激光下降区间的偶次谐波强度减弱;但是,一些来源于激光上升区间的偶次谐波逐渐增强.     

ZnS:V3+光学和顺磁性质的理论研究

应用V^3 的Watson自洽场d-轨函计算出了Racah静电参量A0、B0、C0和用完全对角化方法计算了ZnS：V^3 的光谱和基态g因子，并比较了Racah静电参量A0对光谱能级的贡献，计算结果与实验结果符合得较好。此外，还讨论了共价因子对能级的影响。