H+4形成机制的初步研究

利用Penningiontrap存储和累积离子的功能,获得不同延时（即反应时间）的离子谱H+n(n≤4),不仅进一步证实了H+4具有稳定结构的理论预言,而且经分析得出,H+4是经碰撞反应H+2+H2→H+4;H+3+H+H2→H+4+H2产生的。     

H4+的稳定性及形成和分解过程实验研究

利用Penning ion trap获得了七种不同延时时间(即反应时间)的离子谱Hn+(n≤4),用充分的实验数据证实了H4+是稳定的,稳定时间达1秒量级。实验结果显示：H4+是经合成反应H2++H2→H4+,H3++H+H2→H4++H2产生的;H4+的分解产物是H3++H。分析得出：H4+构型为H3+-核构型。     

H+4团簇离子和它的中性团簇产物H3

报道了关于H+4团簇的实验研究结果,从H+4的分解能谱发现可能存在H3团簇.分析讨论了H+4的形成方式和可能的分解途径.     

[Au(PH_3)]~+芳香基发光材料的光谱性质研究

用二阶微扰(MP2)法和单激发组态相互作用(CIS)法分别优化了发光材料H3PAuPh和(H3PAu)2(1,4-C6H4)2的基态和激发态的几何结构,并用含时密度泛函(TD-DFT)法计算了各发光材料的吸收光谱与磷光发射光谱。计算结果表明,H3PAuPh和(H3PAu)2(1,4-C6H4)2的磷光发射光谱均具有在Au(6p)→C(2p)的金属向配体的电荷转移(MLCT)参与下的pπ*(Ph)→pπ(Ph)跃迁的本质,并伴有Au(6p)→Au(5d)的金属中心电荷转移(MCCT)的性质。(H3PAu)2(1,4-C6H4)2是由两个H3PAuPh连接而成的。因此(H3PAu)2(1,4-C6H4)2的分子轨道也是由H3PAuPh的分子轨道组合而成的。在磷光发射中,由于轨道组合中存在pπ*或pπ的相互作用,所以(H3PAu)2(1,4-C6H4)2的最低能量磷光发射光谱谱线的波长大于H3PAuPh的相应值。     

用密度泛函方法研究质子化苯基丙酮-水团簇

应用密度泛函B3LYP/631+G(d,p)计算方法,对质子化苯基丙酮水团簇这个弱相互作用体系进行了全自由度能量梯度优化,得到该系列团簇的稳定结构.结果表明,H+C8H8OH2O团簇的形成过程为一无能垒的反应过程,在质子与C8H8O分子中O原子的距离为1.015时达到平衡几何.对H+C8H8O(H2O)n(n=1,2,3)团簇,质子位于C8H8O分子和水分子之间,且随着团簇尺寸的增加,质子与C8H8O分子中O原子之间的距离也增加;C8H8OH+H2O可以视为溶剂壳.而对H+C8H8O(H2O)n(n=4,5,6,7,8)团簇,质子位于两个水分子之间,形成H5O2+结构,即C8H8OH5O2+为该系列团簇的中心结构,新增加的水分子以从不同方向进攻这个中心的方式形成更大尺寸的团簇.     

Coincident fragment detection in strong field photoionization and dissociation of H2

Electron-ion momentum spectroscopy is used to investigate the correlated electronic and nuclear motion in fragmentation of H2 in 4 x 10(14) W/cm(2), 25 fs laser pulses at 795 nm. Reaction channel dependent photoelectron spectra indicate that besides the main, stepwise H2 ionization H2(+) dissociation mechanism resulting in the products H(1s) + H(+) + e(-) a second new mechanism has to be assumed. The momentum distribution of H(+) ions in the dissociation channels H(1s) + H(+) + e(-) and 2H(+) + 2e(-) is found to be independent of the kinetic energy of the photoelectrons.     

Electron- or hole-assisted reactions of H defects in hydrogen-bonded KDP

We present an ab initio study of the stability and defect reactions of neutral and charged H interstitial (H(i)) and H vacancy (H(v)) in KH2PO4 (KDP). We find that while there is no interaction between the neutral H(i) and the host, the addition of an electron leads to the ejection of a H host atom and the subsequent formation of an interstitial H2 molecule and a H(v). In sharp contrast, the addition of a hole results in the formation of a hydroxyl bond. Thus, H(i) in both charged states severs the H-bonded network. For the H(v), the addition of a hole leads to the formation of a peroxyl bridge. The neutral H(i) and the positively charged H(v) induce states in the gap. The results elucidate the underlying atomic mechanism for the defect reactions suggested by experiment.     

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利用分子动力学方法研究了H原子与C/Be样品的相互作用过程,当H原子轰击C/Be样品时,发现有一些H原子渗入样品中并且滞留在样品中,H原子的滞留率随H原子的初始入射能量的升高呈线性增长,有些沉积在样品中H原子与C原子相互作用形成H-C键。溅射产物以H原子和H2分子为主。H和H2的产额率随初始入射能量的变化趋势相反,分析了不同机制下产物H和H2的产额率随初始入射能量的关系,且通过分析H原子的入射能量和样品的原子密度的关系来研究轰击后的样品,发现样品中原子分布变化很小,同时分析了化合物中的化学键分布变化较小,只是其化学键的分布峰向样品表面移动。     

提高非晶硅/微晶硅叠层太阳电池光稳定性的研究

如何提高硅基薄膜太阳电池的光稳定性是硅基薄膜太阳电池研究和产业化过程中非常重要的问题. 为了提高非晶硅/微晶硅叠层电池的光稳定性, 本文首先给出了良好光稳定性非晶硅顶电池的结果, 然后重点研究了N/P隧穿结和微晶硅底电池本征层硅烷浓度梯度对叠层电池光稳定性的影响. 经过初步优化, 连续光照1000 h后非晶硅/微晶硅叠层电池的最小光致衰退率只有7%.     

Electron microscopy study of tubular crystals (BiS)1+delta(NbS2)n

Big crystals (mm-sized) with anomalous tubular morphology were synthesised in the Bi-Nb-S system. Their structural study by electron microscopy and related techniques revealed that they can be described as misfit layer structures, a type of composite modulated structures. The misfit monolayer approximately BiNbS3 and bilayer approximately BiNb2S5 phases appear as well in the preparation but with lamellar morphology as it is typical for these kind of compounds. They consist of periodical intergrowth of pseudotetragonal layers BiS (Q) with pseudohexagonal layers NbS2 (H). approximately BiNbS3 has a stacking sequence ...Q,H,Q,H,... and approximately BiNb2S5 has a stacking sequence ...Q,H,H,Q,H,H,... Backscattered electron imaging, wavelength dispersive X-ray spectroscopy and transmission electron microscopy of transversal cross-sections of single tubular crystals showed that these crystals present a strong compositional and inter-laminar stacking disorder along the tube radius. This disorder is suggested to be the cause for the original wrapping of the layers that gives rise to the tubes. Besides the disordered areas, some ordered slabs have been found with stacking sequences corresponding to binary 3R-NbS2 (approximately 6 A), approximately BiNb2S5 (approximately 17.4 A) (which dominate in the crystal) and to a new related phase approximately BiNb4S9 with a stacking sequence ...Q,H,H,H,H,Q,H,H,H,H,... and a periodicity of approximately 29.2 A.     

Electron spin resonance spectroscopy of molecules in large precessional motion: a case of H6(+) and H4D2(+) in solid parahydrogen

We have measured electron spin resonance (ESR) spectra of H6+ and H4D2(+) ions produced in gamma-ray irradiated solid parahydrogen. Anisotropic hyperfine-coupling constants for H6(+) and H4D2(+) determined by the analysis of ESR lines at 4.2K were -0.06 and -0.12 mT, respectively, which were opposite in sign to and much smaller than theoretical results of 1.17-1.25 mT. Although no change was observed in H6(+), the constant for H4D2(+) increased to be 1.17 mT at 1.7 K, which is very close to the theoretical value. We concluded that H6+ both at 4.2 and 1.7 K and H4D2(+) at 4.2K should be in a large precessional motion with the angle of 57-59 degrees, but the precession of H4D2(+) is stopped at 1.7 K.     

KH2PO4中电子或空穴辅助下的氢缺陷反应

研究了非线性光学晶体材料KH2 PO4(KDP)中不同带电状态的H缺陷的稳定性及其反应 .从而以清晰的物理图像描绘了KDP材料暴露在强紫外线或X射线下性能下降的原因 .研究发现 ,对于H间隙原子 ,当增加一个电子时 ,H间隙原子与主H原子发生作用 ,形成间隙H2 分子并产生一个H空位 ,而增加一个空穴时H间隙原子与临近的主O原子形成氢氧键 ,这两种带电态的H间隙原子均切断KDP材料中形成网络的氢键 ;对于H空位 ,增加一个空穴将导致形成“过氧化氢”桥结构 .这些结果在原子层次上清楚地解释了实验所建议的缺陷反应机制     

Tm~(3+)/Yb~(3+)共掺氟氧化物碲酸盐玻璃的上转换发光及光学温度传感

采用高温熔融淬火法成功的合成了Tm~(3+)/Yb~(3+)共掺杂的含有不同浓度Tm~(3+)的氟氧化物碲酸盐玻璃.测量了样品的吸收光谱,结果表明Yb~(3+)和Tm~(3+)成功掺入到玻璃基质中.在980nm激发下,样品在801nm(3H4→3H6)发射最强,在476nm(1G4→3H6)和651nm(1G4→3F4)发射较弱;分析了上转换发光强度与Tm~(3+)浓度依赖关系,确定了上转换发光的最佳掺杂浓度为0.1%Tm2O3;探讨Tm~(3+)的上转换发光机理和Tm~(3+)的浓度猝灭机理,结果表明在980nm激发下Tm~(3+)获得的能量主要来自于Yb~(3+)→Tm~(3+)的量传递,Tm~(3+)的浓度猝灭机理为Tm~(3+)-Tm~(3+)之间的交叉弛豫导致的无辐射能量传递,根据能量匹配的原则,给出可能的交叉弛豫通道.此外,在980nm激发以3F2,3和3H4作为热耦合能级研究分析了Tm~(3+)在氟氧化物碲酸盐玻璃中的温度传感性能,结果表明灵敏度随温度的升高而升高,说明Tm~(3+)掺杂的氟氧化物碲酸盐玻璃可以作为光纤传感材料,且在高温灵敏度更佳.     

H+2离子和H原子相互作用研究

应用改进的排列通道量子力学方法(ACQM)对H+2离子与H原子的相互作用进行了研究.研究结果表明,H+2离子与H原子相互作用能够形成稳定的正三角形构型的H+3离子,从而为实验上制备H+3离子找到了一种新的方法.     

二正丁基锡三齿酰腙Schiff碱配合物的合成和红外光谱研究

合成了 4种三齿酰腙Schiff碱配体H2 L [H2 L1 :C6 H5C(O)NHN =CHC6 H4OH 2 ,H2 L2 :C6 H5C(O)NHN =CHC6 H3(OH) 2 2 ,4,H2 L3:NC5H4C(O)NHN =CHC6 H4OH 2 ,H2 L4:NC5H4C(O)NHN =CHC6 H3(OH) 2 2 ,4]和它们的二正丁基锡新型配合物 (n Bu) 2 SnL ,通过元素分析确定了这些配合物的组成 ,并对配合物在 4 0 0 0～ 40 0cm- 1范围内的主要红外光谱吸收峰进行了归属和讨论 ,推测出配合物可能的分子结构。     

Imaging of a vortex lattice transition in YNi2B2C by scanning tunneling spectroscopy

The vortex lattices in YNi2B2C under the magnetic fields H up to 3 T applied along both the a and the c axes have been studied by scanning tunneling spectroscopy at 4.2 K. The vortex lattice transition has been found to occur in different manners for H parallela and H parallelc; in H parallela a slightly distorted hexagonal vortex lattice has been found to transform to a nearly square one above 1.0 T with increasing H, while in H parallelc the transition occurs at a much lower field around 0.1 T. The unconventional steep increase of the quasiparticle density of states outside the vortex core has also been found well below H(c2).     

(H2O)n (n=1-3)和H2SO4作用下H2CO3气相分解反应机理的理论研究

本文利用CCSD(T)/6-311++(3df,3pd)//B3LYP-D3/6-311++G(3df,3pd)+ 0.9686×ZPE理论方法对(H2O)n (n=1-3)和H2SO4存在与不存在的情况下,H2CO3气相分解反应机理进行了理论研究。计算结果表明(H2O)n (n=1-3)和H2SO4都能使H2CO3气相分解反应的能垒显著地降低,其催化能力按由强到弱的顺序是H2SO4>(H2O)2>(H2O)3>H2O。     

Anisotropies of the lower and upper critical fields in MgB2 single crystals

The temperature dependence of the upper (H(c2)) and lower (H(c1)) critical fields has been deduced from Hall probe magnetization measurements of high quality MgB2 single crystals along the two main crystallographic directions. We show that Gamma(H(c2))=H(c2 axially ab)/H(c2 axially c) and Gamma(H(c1))=H(c1 axially c)/H(c1 axially ab) differ significantly at low temperature (being approximately 5 and approximately 1, respectively) and have opposite temperature dependencies. We suggest that MgB2 can be described by a single field dependent anisotropy parameter gamma(H) (=lambda(c)/lambda(ab)=xi(ab)/xi(c)) that increases from Gamma(H(c1)) at low field to Gamma(H(c2)) at high field.     

Vacancy trapping mechanism for multiple hydrogen and helium in beryllium: a first-principles study

The microscopic mechanism for H and He trapping by vacancy defects and bubble formation in a Be host lattice is investigated using first-principles calculations. A single He atom prefers to occupy a vacancy centre while H does not. He can segregate towards the vacancy from the interstitial site much more easily than H. Both H and He exhibit lower diffusion barriers from a remote interstitial to a vacancy with regard to their diffusion barriers inside a perfect Be solid. Up to five H or 12 He atoms can be accommodated into the monovacancy space, and the Be-He interaction is much weaker than Be-H. The physical origin for aggregation of multiple H or He atoms in a vacancy is further discussed. The strong tendency of H and He trapping at vacancies provides an explanation for why H and He bubbles were experimentally observed at vacancy defects in materials. We therefore argue that vacancies provide a primary nucleation site for bubbles of H and He gases inside Be materials.     

用原子轨道强耦合方法研究H(1s)+H(2s)碰撞的反应截面

采用单电子的双中心原子轨道强耦合方法,计算了H(1s)+H(2s)碰撞体系H(2s)失去电子过程的总截面,并与前人的实验结果进行了比较.研究表明,采用双中心原子轨道强耦合方法得到的H(1s)+H(2s)体系H(2s)失去电子过程的截面与实验比较符合.同时,还给出了H(1s)+H(2s)碰撞体系H(2s)电离过程、H(1s)俘获电子过程和H(2s)退激发到H(1s)过程的理论截面.