Hel photoelectron spectroscopic (PES) and quantum chemistry study on the dimeric compound of 2(5H) furanone

The HeI photoelectron (PE) spectra of both 2(5H) furanone and its trans-chair-dimenc-compound (t-c-DFN) are reported.The assignment of the PES bands is made on the basis of band shapes,the PES results of the molecules which have the similar atomic groups,and the restricted Hartree-Fock (RHF) calculations for the molecules studied.From the results of both PES experimental and theoretical calculations,it is proved that the ionization potential (IPs) of the HOMO for the dimenc-compound is lower than that of the HOMO for the monomer.And the total energy computed for the t-c-DFN is the lowest in the four possible configurations of dimeric-compounds of 2(5H) furanone Therefore the synthesis of t-c-DFN is also the easiest.     

微波消解样品-电感耦合等离子体原子发射光谱法测定锌精矿中镉、砷和汞

锌精矿是近年来我国进口的大宗资源性商品之一,其中含有镉、砷和汞等多种微量有害金属元素,在加工冶炼过程中,这些微量有害金属元素不但影响产品的质量,降低冶炼价值,而且会从相对封闭的环境进入开放的环境,对人类环境产生污染,严重危害人们的身体健康,因此,测定并严格控制进口锌精矿中有害金属元素含量非常重要。国家标准GB20424—2006《重金属精矿产品中有害元素的限量规范》已限制锌精矿中镉、砷、汞有害金属元素含量,后     

银线草和多穗金粟兰中宏量和微量元素的比较分析

采用微波消解-火焰原子吸收光谱法测定秦岭山区2种金粟兰属药用植物银线草和多穗金粟兰中铁、锌、铜、锰、钙、镁、钠、钾的含量。结果显示:银线草和多穗金粟兰中含有丰富的宏量和微量元素,银线草中所测元素含量依次为KCaNaMgFeZnMnCu,多穗金粟兰为KCaMgNaFeMnZnCu;所测得的8种元素中,银线草中的含量均高于多穗金粟兰,加标回收率在95.7%—108.2%之间,相对标准偏差(RSD)均小于5%。该方法简便、快捷、灵敏、准确,为探讨微量元素与银线草和多穗金粟兰的药效关系及进一步开发利用提供了理论依据。     

MSA-DUO-ICP-AES测定菜园土壤中高关注重金属预处理探讨

比较加入几种不同的混酸,用微波消解仪对土壤样品进行消解,采用双向视电感耦合发射光谱仪(DUO-ICP-AES)标准加入法(MSA)测定土壤中6项重金属元素含量。研究表明,HNO3-HClO4-HF-HCl处理土壤的效果比王水、HNO3-HF更佳,同时该法快速简单,回收率和精密度较好,干扰少,为土壤重金属含量的快速测定开辟了新方法。     

HCN和氯反应动态学及产物振动态分布的计算

采用自洽场分子轨道UHF／6－311G**从头计算法,获得了HCN＋Cl→HCl＋CN反应的内禀反应坐标（IRC）。沿着IRC,计算了反应的动态学性质,根据传统过渡态、变分过渡态理论,得到了反应的理论速率常数,可供实验工作者参考,利用SCP－IOS近似下的产物振动跃迁几率公式,自编程序计算了HCN（004,302）＋Cl→HCl＋CN反应中产物CN的振动态分布,获得了和实验相一致的结果。     

分子内坐标下反应途径性质的理论研究

给出了分子内坐标下反应途径的动力学性质 ,即垂直于IRC的振动频率ωK和振动模式LK,这些振动模式与沿IRC运动的耦合常数BKF及它们之间彼此的耦合常数BKL.通过建立一套分子内坐标下的反应途径理论 ,以H1O2 H3 H4→H1O2 H3 H4反应为例 ,证明给出的这些动力学性质BKL,ωK,BKF清楚地说明了在化学反应中各化学键 (包括键角 )的相互作用、变化情况及各自对反应的贡献 .     

Molecular structure of diatomic lanthanide compounds

The molecular constants of selected diatomic lanthanide compounds (LaH, LaO, LaF, EuH, EuO, EuF, EuS, GdO, GdF, GdH, YbH, YbO, YbF, YbS, LuH, LuO and LuF) have been calculated by using relativistic small-core pseudopotentials and optimized (14s13p10d8f6g)/ [6s6p5d4f3g] valence basis sets. The results are in good agreement with available experimental data, with exception of YbO and LuF. The reasons for the discrepancies in case of YbO are due to a complicated mixing of configurations in the ground state, whereas in case of LuF the binding energy estimated by experimentalists appears to be too low.     

镍电极在KOH水溶液中析氧行为的研究

用恒电流法测试在２２－７０℃之间电解３０ｗｔ％ＫＯＨ水溶液对Ｎｉ阳极的稳态极化曲线以及该过程的交换电流密度ｉ０，Ｔａｆｅｌ斜率ｂ传递系数β和不同电流密度下的析氧电位随电解温度的变化关系，结果发现：４０℃是各参量随温度变化的一个突出突点，４０℃以下，高过电位区的Ｔａｆｅｌ斜率达１２０ｍＶ以上，低过电位区的反应活化能Ｅａ为７９．８８ｋＪ／ｍｏｌ，而４０℃以上时，位区的Ｔａｆｅｌ斜率达１２０ｍＶ以上，低     

有机化学蒸馏实验中的物理化学知识点

以有机化学实验中的蒸馏技术为实例,联系相平衡、界面现象等内容,组织讨论有机化学蒸馏实验中的物理化学知识点,旨在进一步培养学生的学习兴趣和科学的学习方法。     

Theoretical study of dynamical properties on reaction path in molecular internal coordinates

The dynamical properties on reaction path (IRC) in internal coordinates have been obtained, which in. clude ω_K (frequencies orthogonal to IRC), L_K (vibrational modes), B_(KF) (coupling constants between the IRC and vibra tions orthogonal to it), B_(KL) (coupling constants between every two vibrations orthogonal to IRC). A set of theory of teac. tion path in molecular internal coordinates has been also constructed. The dynamical properties, including ω_K, B_(KF) B_(KL) of the reaction H~1O~2H~3 H~4→H~1O~2 H~3H~4 have been calculated, which explicitly explain the interaction, chang ing trend and contribution of each chemical bond (including bond angle) in the reaction.