一维链状氰根桥联配合物[Pr(bet)_2(H_2O)_3Fe(CN)_6]_n的合成、晶体结构和磁性

以K3Fe(CN) 6 ,甜菜碱和Pr(NO3) 3·6H2 O合成了一维链状氰根桥联配合物 [Pr(bet) 2 (H2 O) 3Fe(CN) 6 ] n,并通过元素分析、红外光谱进行了表征。利用单晶X射线四圆衍射测定了配合物的晶体结构 ,晶体属正交晶系 ,P2 1 2 1 2 1 空间群 ,晶胞参数a =0 9634 ( 2 )nm ,b =1 45 5 6( 3)nm ,c =1 7798( 9)nm ,V =2 495 9( 9)nm3,Dc=1 70 6Mg·m3,Z =4,GOF =0 970 ,F( 0 0 0 ) =12 84,R1 =0 0 30 7。变温磁化率 ( 1 8～ 30 0K)表明在Pr3 和Fe3 离子间存在弱的反铁磁相互作用。     

BCl3分子振动频率的同位素效应

利用密度泛函B3LYP方法与耦合簇CCSD方法,结合全电子高斯基函数,计算了¹⁰BCl₃和¹¹BCl₃分子的基态平衡几何和谐振频率,进而得到了分子伸缩振动模式的同位素位移.计算检验了芯-价电子关联、标量相对论效应,以及基组外推对分子几何结构、振动频率和同位素位移的影响;结果表明,高阶修正效应对同位素位移的影响很小,并分析了其原因.同时得到了不同Cl/B同位素分子体系的同位素位移.研究对激光分离同位素技术中激光中心波长的选择具有重要参考意义.     

Spectroscopic properties and radiative lifetimes of SiTe:A high-level multireference configuration interaction investigation

The 18 A-S states correlated to the lowest dissociation limit of SiTe were calculated by using a high-level multirefer-ence configuration interaction （MRCI） method, including scalar relativistic and spin-orbit coupling effects. Based on the calculated potential energy curves, the spectroscopic constants of bound states were determined, which are well consistent with previous experimental results. The spin-orbit matrix elements between the A-S states were computed, which lead to an in-deoth understanding, of oerturbations on the electronic state a^3∏. Finally. the transition dioole moments of allowed transitionsA^1∏-X^1∑^＋,E^1∑^＋-X^1∑^＋,a^3∏-d^3△,a^3∏-d^3△,a^∏-a′^3∑^＋,a^3∏-e^3∑^-,and the radiative lifetimes of A^1∏,E^1∑^＋,and a^3∏ were evaluated.     

Accurate spectroscopic constants of the lowest two electronic states in S_2 molecule with explicitly correlated method

A computational scheme for accurate spectroscopic constants was presented in this work and applied to the lowest two electronic states of sulfur dimer. A high-level ab initio calculation utilizing explicitly correlated multireference configuration interaction method(MRCI-F12) was performed to compute the potential energy curves(PECs) of the ground triplet X3-Σgand first excited singlet a1?g states of sulfur dimer with cc-p CVX Z-F12(X = T, Q) basis sets. The effects of Davidson modification, core–valence correlation correction, and scalar relativistic correction on the spectroscopic constants were examined. The vibration–rotation spectra of the two electronic states were provided. Our computational results show excellent agreement with existing available experimental values, and the errors of main spectroscopic constants are within 0.1% order of magnitude. The present computational scheme is cheap and accurate, which is expected for extensive investigations on the potential energy curves or surfaces of other molecular systems.     

CO分子四个电子态的振转谱:两种效应修正方法的比较

基于完全活性空间自洽场方法和多参考组态相互作用（multi-reference configuration interaction method,MRCI）方法,采用MRCI+Q/CBS（TQ5）+CV+SR（方法A）和aug-cc-pwCVnZ-DK（n=T,Q,5）（方法B）方案,分别计算了包含Davidson修正（+Q）、芯-价电子关联（core-valence correlation correction,CV）效应以及标量相对论（scalar relativistic,SR）效应的CO分子的基态X¹∑⁺和激发态a³Π,a'³∑⁺和A¹Π的势能曲线.在此基础上,获得了这些电子态的振-转谱.通过与实验结果比较发现：方法A适合a'³∑⁺和A¹Π等较高激发态的振-转谱的计算,方法B更适合基态X¹∑⁺和第一激发态a³Π的振-转谱的精细计算.该研究可以为其他小分子高精度振-转谱快速计算方案选择提供参考.     

丁酮异构化的势能面分析

用密度泛函理论计算研究了丁酮异构化的势能面. 通过IRC方法确定了丁酮异构化的6个主要反应路径,相应的产物分别为1-丁烯-2-醇、2-丁烯-2-醇、丁醛或1-丁烯-1-醇、丙烯基甲醚、甲基烯丙基醚和乙烯基乙醚. 其中3个路径经过环氧丁烷,表明环氧丁烷是丁酮异构化过程中重要的中间产物. 计算得到的反应物和产物的垂直电离能与现有的实验值吻合得很好. 通过过渡态的相对能量和高能垒的数目比较,认为最可行的丁酮异构化反应路径是丁酮→1-丁烯-2-醇→2-丁烯-2-醇.     

CH4+O2体系中碰撞-诱导O2（X3∑g-→a1△g)跃迁几率计算

采用从头计算二阶自旋-轨道多组态准简并微扰理论计算了CH4+O2体系中O2分子X3∑-g-a1Δg, X3∑-g-b1∑+g和b1∑+g-a1Δg的碰撞-诱导跃迁几率,分析了O2分子振动对跃迁几率的影响,并与O2+H2模型的结果做了比较.     

He-S2(B3∑-u→X3∑-g) van der Waals体系的从头计算

利用多参考组态相互作用方法计算得到了He-S2(X3∑-g)与He-S2(B3∑-u)的势能曲面;计算并讨论了He原子与S2分子的相对位置R与S2(B3∑-u→X3∑-g)跃迁矩和诱导偶极矩变化的关系;分析了He对S2分子轨道的压缩随R的变化,以及在实验中加入缓冲气体对实现S2分子发光的影响.     

Multireference calculation of lifetime of A~2Π_u state in nitrogen-molecule cation

This paper utilizes multireference configuration interaction theory to calculate the lifetime of A2Πu state for nitrogen molecular ion N+2.It obtains the transition moment function for A2Πu→X2Σ+ g,Franck-Condon factors between vibrational levels of the two states.The calculated lifetimes are 16.81,14.62,13.10,12.18,11.40,and 11.64 μs forv'= 0,1,2,3,4,5 vibrational levels of A2Πu state,respectively,which are in excellent agreement with available experimental values.     

CH_3I~(2+)的二体、三体解离过程的理论研究

采用密度泛函和耦合簇理论从过渡态的观点对CH_3I~(2+)离子的解离过程进行了计算和分析.优化得到了CH_3I,CH_3I+和CH_3I~(2+)的稳定结构及解离过渡态的几何构型并给出了相应能量,计算的第一、二电离能与实验结果符合.基于母体离子、过渡态和解离碎片的几何结构和能量,对CH_3I~(2+)的两体解离过程和三体解离过程进行了详细分析和讨论.给出了二体、三体解离的可能解离通道,并分析了实验上观测到的解离碎片离子的产生机制.计算结果表明,三重和单重绝热势能面上的一些解离过程表现出明显的差异.