酸根离子及其水溶液对镎酰离子结构性质的影响

利用B3LYP杂化密度泛函方法,在相对论有效芯势模型下,优化得到了NpO22+离子及其配合物在气相和水溶液中的几何结构和电子结构, 研究了NO3-、SO42-和CO32-离子及其水溶液对NpO22+离子的结构和性质的影响.结果表明,NpO22+离子结合各种酸根离子后其Np=O键的键长都有明显增长、Np和O原子的价电子轨道能均有升高,而考虑溶剂化效应后酸根离子的影响将减小.电荷分析发现,结合酸根离子后,NpO22+中Np和O原子间形成的共价键的强度减弱、键长增长.对NpO22+离子与三种酸根离子的理论结合能的比较显示,NpO2CO3分子最为稳定.     

酸根离子及其水溶液对镎酰离子结构性质的影响

利用B3LYP杂化密度泛函方法,在相对论有效芯势模型下,优化得到了NpO_2~(2+)离子及其配合物在气相和水溶液中的几何结构和电子结构,研究了NO-3、SO2-4和CO2-3离子及其水溶液对NpO_2~(2+)离子的结构和性质的影响.结果表明,NpO_2~(2+)离子结合各种酸根离子后其Np=O键的键长都有明显增长、Np和O原子的价电子轨道能均有升高,而考虑溶剂化效应后酸根离子的影响将减小.电荷分析发现,结合酸根离子后,NpO_2~(2+)中Np和O原子间形成的共价键的强度减弱、键长增长.对NpO_2~(2+)离子与三种酸根离子的理论结合能的比较显示,Np O2CO3分子最为稳定.     

GeFe2O4晶体的基态能级和零场分裂参量

GeFe2O4是一种单晶化合物,考虑到由3个〈111〉方向之一的一个轴,从一个中心位置到另一个中心位置之间,以Fe2+离子为中心离子和O2-为配体构成了三角(C3v)对称体系.利用不可约张量理论,建立了3d4/3d6离子三角(C3v)对称的晶体场和自旋相互作用哈密顿矩阵,因此,由完全对角化的晶体场和自旋-轨道相互作用哈密顿矩阵和电子顺磁共振理论公式求出单晶GeFe2O4中Fe2+离子的电子顺磁共振零场分裂参量D和F-a.并研究了自旋三重态对电子顺磁共振(EPR)零场分裂的贡献.结果显示自旋三重态对基态零场分裂的贡献是较强的,理论计算结果与实验值相符.     

溶剂热合成法制备的Zn1-xMnxO和Zn1-2xMnxLixO纳米材料的磁学性质

用溶剂热合成法在160oC制备出Zn_1-xMn_xO纳米棒和Zn_1-2xMn_xLi_xO纳米颗粒. XRD和拉曼测试结果表明Mn离子已很好地掺入ZnO母体中. M-H图中未观察到磁回滞,ESR谱中的精细结构说明掺杂的Mn离子间没有铁磁相互作用. 共掺Li仅仅改变了产物的形貌,并不能改变其磁学性质.     

H3O+, NO+和O+·2离子同九种烷氧基醇化合物反应的研究

在用选择离子流动管质谱(SIFT-MS)分析常用指甲油清洗垫发现大量4-丁酸内脂(γ-butyrolactone, GBL)和2-丁氧基乙醇(2-butoxy-1-ethanol)等挥发性气体后, 运用选择离子流动管(SIFT)对H3O , NO 和O ·2离子同九种烷氧基醇化合物(R1-O-R2OH)之间的反应进行了研究. 获得了这些反应在潮湿空气条件下进行的情况, 并运用产物离子水合物的种类和分布来确认产物离子的结构和反应机理. 还研究了在不同载气压力下进行的反应. 结果表明, 这些化合物同H3O 和NO 的反应都是先生成初生态离子-分子络合物, (H3O .M)*和(NO .M)*, 然后经不同反应渠道生成各种离子产物. 这些初生态络合物同反应体系中存在的气体分子(如氦气, 氮气和氧气分子)的碰撞对最终离子产物的形成和分布也有影响. 这些化合物同O2 ·反应会生成各种离解碎片离子, 但不能确定这些离子是否经由初生态络合物(O2 ·.M)*生成. 该项研究提供了用SIFT-MS在空气和潮湿气体中分析这些化合物所需的反应速率常数和离子产物等动力学数据, 并将进一步应用到药物成瘾及滥用和呼吸道疾病的诊断和分析等领域.     

Ho3+掺杂GeO2-Ga2O3-Li2O-BaO-La2O3玻璃的光谱和增益特性的计算

用高温熔融法制备了不同Ho3+浓度掺杂的65GeO2-12Ga2O3-8Li2O-10BaO-5La2O3-χHo2O3锗酸盐玻璃.从吸收光谱出发,应用Judd-Ofelt理论,获得了Ho3+离子的跃迁强度参量（Ω2,Ω4,Ω6）,并由此计算了Ho3+离子的自发辐射跃迁几率A,荧光分支比β,辐射能级寿命τ等光谱参量.根据McCumber理论,计算了Ho3+离子能级5I8→5I7（2.0 μm）跃迁的吸收截面和受激发射截面,同时也获得了相应的反映粒子数反转的增益截面光谱.钬掺杂的锗酸盐玻璃,其增益截面的最大值比所报道的氟锆铝酸盐玻璃大.结果表明,Ho3+掺杂的锗酸盐玻璃在2.0 μm附近波段的中红外激光器中将有一定的应用前景.     

掺铒铋酸盐玻璃的光谱性质和热稳定性研究

测试了铋酸盐玻璃(85-x)Bi2O3-(10+x)B2O３-5Na2O(x=0，5，10，15，20，25 mol%)中Er3+离子的吸收光谱、荧光光谱、荧光寿命及热稳定性.应用Judd-Ofelt理论计算了铋酸盐玻璃中Er3+离子的强度参数(Ω2=(352—386)×10-20cm2,Ω4=(138—152)×10-20cm2,Ω6=(093—117)×10-20cm2),应用McCumber理论计算了Er3+离子的受激发射截面(σe=(70—95)×10-21cm2)及Er3+离子4I13/2→4I15/2发射谱的荧光半高宽(FWHM=57—79nm)，测得了Er3+离子４I13/2能级荧光寿命(τm=265—159ms)，分析了玻璃的热稳定性能.研究了Er3+离子各种光谱参数对成分的依赖性，发现随着玻璃中B2O3含量的增加，强度参数Ωt(t=2,4,6)、荧光半高宽(FWHM)、热稳定性均相应增加，而测得的荧光寿命却减小.比较了不同基质玻璃中Er3+离子的光谱特性，结果表明掺铒铋酸盐玻璃更适合于掺Er3+光纤放大器实现宽带和高增益放大. 关键词： 铋酸盐玻璃 光谱性质 成分依赖性 Er3+离子     

化学计量的氧化钠团簇阳离子结构的离子迁移质谱法研究（英文）

本文通过离子迁移质谱法研究了氧化钠团簇阳离子(Na_nO_m~+,n≤11)的稳定结构.质谱结果表明化学计量组成Na(Na_2O)_((n-1)/2)~+(n=3、5、7、9和11)系列是稳定的,并且NaO(Na_2O)_((n-1)/2)~+(n=5、7、9和11)系列作为二级稳定系列.为了获得这些团簇离子的结构,通过离子迁移率测量实验测定离子和氦缓冲气体之间的碰撞截面.同时计算了这些组合物优化结构的理论碰撞截面.结果表明,Na(Na_2O)_((n-1)/2)~+和NaO(Na_2O)_((n-1)/2)~+的结构除了n=9之外,其它具有相似结构框架.Na(Na_2O)_((n-1)/2)~+所有的化合键位于钠和氧之间.另一方面,NaO(Na_2O)_((n-1)/2)~+中除了Na-O键之外,还存在一个O-O氧键,表明NaO(Na_2O)_((n-1)/2)~+具有过氧化物离子(O_2~(2-))作为Na(Na_2O)_((n-1)/2)~+的氧化物离子(O~(2-))的替代物.Na(Na_2O)_((n-1)/2)~+和NaO(Na_2O)_((n-1)/2)~+两种稳定系列都是闭壳组合物.这些闭壳特征对氧化钠簇阳离子的稳定性具有强烈影响.     

激光偏振特性对丙酮和氧气多光子电离质谱信号的影响

在极性分子丙酮复合物CH3COCH3*H2O和非极性分子氧气的REMPI谱中,母体离子信号强度与激光偏振方向的关系是不同的.改变532 nm激光偏振方向,记录了两种分子母体离子信号强度,实验结果表明,对于氧气分子的母体离子信号强度,激光偏振方向的改变对其没有影响,而对于CH3COCH3*H2O的母体离子信号强度,随偶极矩与激光偏振方向夹角的增加,其母体离子信号强度呈余弦曲线变化,且与夹角余弦的2.1次幂成正比.理论分析显示,CH3COCH3*H2O的REMPI母体离子信号强度应与此夹角的余弦的2次幂成正比.这就说明实验结果和理论分析是相符的.     

光学材料

光学玻璃TQ171.712007021803掺铒TeO2-B2O3-Nb2O5-ZnO玻璃系统的光谱性质和热稳定性的研究=Investigation on spectral properties and ther-mal stability of Er3+doped TeO2-B2O3-Nb2O5-ZnOglasses[刊,中]/李广坡(宁波大学信息科学与工程学院.浙江,宁波(315211)),徐铁峰…//量子电子学报.-2006,23(4).-461-466制备了碲酸盐玻璃样品70TeO2-(15-x)B2O3-xNb2O5-15ZnO-1%(重量比)Er2O3(TBN,x=0,3,6,9,12,15mol%),测试了玻璃样品的热稳定性和光谱性质。根据Judd-Ofelt理论计算了TBN玻璃中Er3+离子的强度参数,发现随着Nb205含量…     

Hyperfine coupling and large amplitude motions interaction in the water dimer

Experimental and theoretical analyses of the hyperfine structure of the non-rigid water dimer (H₂O)₂ were carried out. Measurements were performed with an FT-MW spectrometer allowing us to resolve most of the hyperfine components. Eight hyperfine patterns were recorded involving rotational-tunneling sublevels with J ? 2. Hyperfine patterns were analyzed accounting for the magnetic spin-rotation and spin-spin hyperfine couplings. Symmetry adapted nuclear spin wavefunctions were built to account for the interaction of the hyperfine coupling with the large amplitude motions displayed by the water dimer and to build total rotational-tunneling-hyperfine wavefunctions obeying the Pauli exclusion principle. This accounts for the strong dependence of the hyperfine patterns on the symmetry species of the rotational-tunneling sublevels. These theoretical results were used to perform individual and global analyses of the hyperfine patterns. The latter analysis yields values for some of the components of the spin-rotation coupling tensors.     

Internal rotation and hyperfine coupling interaction in deuterated acetaldehyde

Theoretical and experimental investigations of the hyperfine structure of deuterated acetaldehyde (CD₃COH) are presented. The theoretical approach accounts for the large amplitude internal rotation of the CD₃ group. A hyperfine Hamiltonian, depending on the large amplitude torsional angle, is written taking into account quadrupole hyperfine coupling arising from the three deuterium atoms. Effective hyperfine coupling Hamiltonians are derived for A- and E-type rotation-torsion levels. In the former case, a very symmetrical operator arises in which the hyperfine coupling is the same for all three deuterium atoms. In the latter case the operators are less symmetrical. Hyperfine levels are calculated using symmetry adapted hyperfine wavefunctions in order to build total hyperfine-rotation-torsion wavefunctions satisfying the Pauli exclusion principle. The theoretical approach is used to carry out analyses of six hyperfine patterns which were recorded using a pulsed molecular beam Fourier transform microwave spectrometer. The experimental resolution of this apparatus allows us to resolve individual hyperfine components in many cases. The results of the analysis are consistent with deuterium atoms having an effective quadrupole coupling tensor which, except for appropriate rotations, is quite close to that in CH₃D.     

Magnetic hyperfine anomalies

This study is concerned with the measurement and interpretation of magnetic hyperfine anomalies in electronic and muonic atoms. i.e. effects of the distribution of nuclear magnetization on the magnetic dipole hyperfine interaction. After a summary of the relevant theory and a review of experimental techniques, hyperfine anomaly results are discussed in terms of various nuclear models. The use of the anomaly for yielding information about the origin of magnetic hyperfine interactions is outlined. Experimental and theoretical hyperfine anomalies are tabulated.     

Anomalous Internal Conversion as a Clue to Solving the <Superscript>209</Superscript>Bi Puzzle

A numerical analysis of the specific-difference (SD) method for eliminating the Bohr–Weisskopf effect in the theory of hyperfine splitting is performed within a more general theory of anomalous nuclear moments. The limiting accuracy of the SD method is demonstrated. In analyzing experimental data on the hyperfine splitting in H- and Li-like ions of ²⁰⁹Bi, it is found that the disagreement between theoretical and experimental results that was reported recently was due to going beyond this theoretical accuracy. Prospects of further experimental and theoretical studies in these realms are discussed.     

Hyperfine interaction of defects in insulators

The study of point defects, other than impurities, in insulators by electron paramagnetic resonance (E.P.R.) and electron nuclear double resonance (E.N.D.O.R.) is discussed. An introduction to the theory of the hyperfine spectra as obtained by E.P.R. and E.N.D.O.R. is presented in order to provide a basis for the discussion of results and their interpretation. Emphasis is placed on how the theory is used to analyse the spectra and how characteristics of the defects such as electronic state and defect geometry are obtained from the analyses. A résumé of the experimental techniques, especially E.N.D.O.R., is presented to give the reader a reasonably current view of the methods for obtaining data. The presentation of experimental results and recent theoretical developments is divided into a discussion of electron excess defects in cubic lattices and one on trapped hole centres in the same lattice type. This is followed by a discussion of these types of defects in non-cubic lattices. Finally the results of measurements on the hyperfine structure of excited states of electron and hole type in cubic crystals are discussed. In all cases an attempt was made to present the details of an illustrative example in order to indicate the salient features of the topic rather than give an exhaustive discussion. Needs for further measurement and future improvements of the theory are indicated.     

Hyperfine structure of higher rovibrational levels in the iodine B state studied by Ar+ laser induced fluorescence

The hyperfine structure of higher rovibrational levels in the iodine B state has been investigated by studying the fluorescence of a well collimated iodine molecular beam excited by the 5017 Å Ar⁺ laser line. Nine transitions: R(13) 61-0, P(12) 61-0, R(49) 67-0, R(39) 64-0, R(26) 62-0, P(56) 73-0, R(54) 70-0, R(55) 77-1, R(51) 68-0 were identified and their center of gravity located to an accuracy of ±0.001 cm^-1. A fit of the theoretically predicted hyperfine patterns to the observed spectra enables one to study the variation of the magnetic hyperfine constant C′ with the vibrational quantum number υ′ in the range 61 ? υ′ ? 73. The observed behavior is well accounted for by a simple theoretical model developed by Vigué et al.     

纳米Mn2O3的制备及其ESR研究

采用通常的化学液相均相沉淀法首次制备出了培养Ｍｎ２Ｏ３材料，Ｘ射线衍射和透射电镜观察表明纳米Ｍｎ２Ｏ３的颗粒在９－５０ｎｍ，９纳米的Ｍｎ２Ｏ３顺磁共振谱图观察到六线峰精细结构，并对此结果进行了合理的讨论。     

Hyperfine anomaly arising from the nuclear spin-forbidden transition,and absolute sign determination of the zero-field splitting constant

It has been found in the triplet E.S.R. spectra of radical pairs in irradiated potassium deuterium fumarate that the hyperfine structure of the two transitions, M _s = 1?0 and M _s = 0?+1, are entirely different. This anomaly has been interpreted in terms of the forbidden transition arising from the mixing of the nuclear spin states by the anisotropic hyperfine interaction. The theory has been developed for multiplet electron spin systems and includes the nuclear Zeeman interaction which is often neglected. The theoretical predictions are in good agreement with the observed separations and intensities of the anomalous hyperfine lines. In addition, it has been found that since the forbidden lines of the electron spin multiplet system with S ≥ 1 appear strongly only in transitions which include some specific electronic spin states, the anomalous features of the spectra make it possible to determine the absolute sign of the zero-field or hyperfine splitting constant, if the sign for one of them is known. Using this principle, attempts have been made to determine the absolute sign of the zero-field splitting constant for a number of triplet E.S.R. spectra which exhibit a hyperfine anomaly arising from the proposed mechanism.     

Laser spectroscopy applied to the study of hyperfine interactions

The impact of laser-spectroscopy techniques on the study of hyperfine interactions is illustrated by chosen examples. A brief survey of the theory of hyperfine interactions is given as well as an overview of the available experimental techniques. Results from alkali atoms, alkaline-earth elements and Group III atoms are given with special emphasis on the studies of electronic properties in sequences of Rydberg states and the investigation of nuclear properties for long chains of isotopes of the same element. Recent developments on the theoretical side, particularly what regards the many-body perturbation approach, are also discussed.     

Comparative studies of the magnetic dipole and electric quadrupole hyperfine constants for the ground and low lying excited states of 25Mg+

We have employed the relativistic coupled cluster theory to calculate the magnetic dipole and electric quadrupole hyperfine constants for the ground and low lying excited states of singly ionized magnesium. Comparison with experimental and the other theoretical results are done and predictions are also made for a few low lying excited states which could be of interest. We have made comparative studies of the important many body effects contributing to the hyperfine constants for the different states of the ion.