叠氮乙烷二聚体分子间相互作用的理论研究

Energetic materials are aggregative and mixed systems. The intermolecular interactions play significantroles in the physical,chemical and explosive property. The study on intermolecular interactions of energetic materials has attracted wide attention. The organic azides are an important category of energetic materials and widely used in many fields. Ethyl azide is the simple model having the explosive property for the organic azides energetic compound. Ethyl azide monomer（Ⅰ）and all its possible stable clusters（Ⅱ,Ⅲ and Ⅳ）are fully optimized by ab initio method at the HF/6-311++G** level. Vibrational frequencies calculated to ascertain each structure are characterized to be the stable structure（no imaginary frequencies）. The proportions of correlated interaction energies to their total interaction energies ΔE（MP2）are 65.14%,63.76% and 65.62% for Ⅱ,Ⅲ and Ⅳ respectively. In addition,the basis set superposition error（BSSE）correction energies are 7.82,7.61 and 4.40 kJ/mol for Ⅱ,Ⅲ and Ⅳ respectively. The zero point energy （ZPE） corrections for the interaction energies are much less than those of MP2 electron correlation and BSSE correction energies. After MP2 electron correlation correction,BSSE and ZPE correction,the greatest corrected intermolecular interaction of the dimers is -10.45 kJ/mol. The charge redistribution mainly occurs on the adjacent N?H atoms between submolecules. The charge transfer between two subsystems is very small. Natural bond orbital（NBO）analysis is performed to reveal the origin of the interaction. Based on the statistical thermodynamic method,the standard thermodynamic functions,heat capacities（C0p）,entropies（S0m）and enthalpies（H0m）and the changes of thermodynamic properties from the monomer to dimer with the temperatures ranging from 200. 00 K to 800. 00 K have been obtained.     

叠氮化氢二聚体的分子间相互作用

通过ａｂ ｉｎｉｔｉｏＨＦ／６－３１Ｇ＊计算求得叠氮化氢二聚体（ＨＮ３）２势能面上四种优化结构型,经ＭＰ４ＳＤＴＱ电子相关校正和基组叠加误差２校正求得这些构型下的分子间相互作用能。结果表明,在四种优化构型中Ｎ３Ｈ．．．ＮＨＮ２最稳定,其分子间相互作用能为－１６．０７ＫＪ．ｍｏｌ＾－１。     

羟基二酰亚胺二聚体分子间相互作用的量子化学研究

采用从头算MP2方法在6-311++G~**基组水平上讨论了CP梯度校正对两种羟基 二酰亚胺异构体所的相互作用能和几何结构的影响，并利用分子中的原子理论（ Atoms in molecules，AIM）计算了五个拓扑参数：键临荷密度、电荷密度的 Iaplacian值、氢键中氢原子的体积、氢原子集居数、氢原子能量来表征氢键的形 成．种构型氢键体系中还讨论了二聚体的相互作用能与氢键临界点的电荷密度、质 子供体X-H键长的线性相关性问题．表明这种线性相关性的存在有范围限制，复合 物和其中单体的构型能够影响这种关系的存在.     

硝酸乙酯分子间相互作用的ab initio 研究

在abinitio-HF/6-31G水平上求得硝酸乙酯二聚体势能面上的四种优化构型和电子结构。经MP2电子相关校正和基组叠加误差(BSSE)以及零点能(ZPE)校正,求得二聚体的最大结合能为11.46kJ.mol^-^1,还进行HF/6-311G和HF/6-311++G水平的总能量比较计算,发现6-31G基组对计算结合能比较适合,二子体系间的电荷转移很少,对优化构型进行振动分析,并基于统计热力学求得从单体形成二聚体的热力学性质变化。     

硝酸甲酯分子间相互作用的DFT和ab initio比较

用密度泛函理论(DFT)和从头算(ab initio)方法,分别在B3LYP/6 31G和HF/6 31G水平上求得硝酸甲酯三种二聚体的全优化几何构型和电子结构,并用6 311G和6 311＋＋G基组进行总能量计算.对HF/6 31G计算结果进行MP4SDTQ电子相关校正.在各基组下均进行基组叠加误差(BSSE)和零点能(ZPE)校正求得结合能.对6 31G优化构型作振动分析并基于统计热力学求得200～600 K温度下单体和二聚体的热力学性质.详细比较两种方法的相应计算结果,发现DFT求得的分子间距离较短,分子内键长较长,所得结合能均小于相应ab initio计算值.     

硝胺及其甲基衍生物的从头计算研究 3: 甲硝胺及其同位素衍生物的谐性力场和振动光谱

用TEXAS从头计算程序,取STO-4-21G基组,计算了甲硝胺的谐性力场和振动光谱.直接理论计算的谐性力场经由其他分子转移来的经验校正因子校正后,提供了甲硝胺振动基频的预测.预测值和甲硝胺分子在气相中的振动光谱实验值之间的平均偏差为31cm^-1.为了获得更合适的气相甲硝胺振动力场和预测它的同位素衍生物的振动光谱,我们优化了一组新的校正因子,使理论值和实验值的平均偏差减为8.9cm^-1.用这组校正因子得到的力场预测了三个同位素衍生物的振动光谱,其同位素位移的理论预测值和实验值符合良好.     

硝胺及其甲基衍生物的从头计算研究 3: 甲硝胺及其同位素衍生物的谐性力场和振动光谱

用TEXAS从头计算程序,取STO-4-21G基组,计算了甲硝胺的谐性力场和振动光谱.直接理论计算的谐性力场经由其他分子转移来的经验校正因子校正后,提供了甲硝胺振动基频的预测.预测值和甲硝胺分子在气相中的振动光谱实验值之间的平均偏差为31cm^-1.为了获得更合适的气相甲硝胺振动力场和预测它的同位素衍生物的振动光谱,我们优化了一组新的校正因子,使理论值和实验值的平均偏差减为8.9cm^-1.用这组校正因子得到的力场预测了三个同位素衍生物的振动光谱,其同位素位移的理论预测值和实验值符合良好.     

N-甲硝胺异构化和分解反应机理和动力学的理论研究

The complex potential energy surface and reaction mechanisms for the unimolecular isomerization and decomposition of methyl-nitramine (CH3NHNO2) were theoretically probed at the QCISD(T)/6-311+G*//B3LYP/6-311+G* level of theory. The results demonstrated that there are four low-lying energy channels: (i) the NN bond fission pathway; (ii) a sequence of isomerization reactions via CH3NN(OH)O; (IS2a); (iii) the HONO elimination pathway; (iv) the isomerization and the dissociation reactions via CH3NHONO (IS3). The rate constants of each initial step (rate-determining step) for these channels were calculated using the canonical transition state theory. The Arrhenius expressions of the channels over the temperature range 298-2000 K are k6(T)=1014:8e-46:0=RT , k7(T)=1013:7e-42:1=RT , k8(T)=1013:6e-51:8=RT and k9(T)=1015:6e-54:3=RT s-1, respectively. The calculated overall rate constants is 6.9￡10-4 at 543 K, which is in good agreement with the experimental data. Based on the analysis of the rate constants, the dominant pathway is the isomerization reaction to form CH3NN(OH)O at low temperatures, while the NN bond fission and the isomerization reaction to produce CH3NHONO are expected to be competitive with the isomerization reaction to form CH3NN(OH)O at high temperatures.     

定标粒子理论研究HPLC分子间相互作用对K'的影响

本文以统计热力学的观点, 对流动相和固定相分别采用定标粒子理论和点阵模型研究HPLC过程中溶质分子与流动相分子、固定相分子之间的相互作用, 得到了描述分子间相互作用与K'之间定量关系的关联方程, 并通过实验对该方程加以验证。     

B炸药主要组分TNT和RDX分子间相互作用的理论研究

在B3LYP/6-31G(d)水平上研究了B炸药的主要成分--2,4,6-三硝基甲苯(TNT)与环三亚甲基三硝胺(RDX)分子间的相互作用, 得到了10种TNT＋RDX的全优化构型. 讨论了稳定构型在几何参数、稳定性、红外光谱和电荷分布上的差异. 借助自然键轨道(NBO)理论揭示了TNT与RDX分子间相互作用的本质, 主要由氢键所贡献. 分子间相互作用能在－3.930～－14.652 kJ•mol^－1之间, 经基组叠加误差(BSSE)校正, 相互作用能顺序为VI＞III＞V＞IV＞X＞I＞IX＞II＞VII＞VIII. 对全优化构型进行了热力学性质的分析, 探讨了由单体分子形成混合体系的热力学性质的变化, 结果发现, 形成分子间氢键是个放热过程. 运用Kamlet-Jacobs方程基于理论密度(ρ)估算了混合体系TNT＋RDX的爆轰性质爆速(D)和爆压(p), 与文献值进行比较表明理论计算方法和结果是可靠的.     

Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Nitroamine Dimers

Ab initio self-consistent field(SCF) and Mφller-Plesset correlation correction methods employing 6-31G^** basis set have been applied to the optimizations of nitroamine dimers.The binding energies have been corrected for the basis set superposition error (BSSE) and the zero-point energy.Theree optimized dimers have been obtained.The BSSE corrected binding energy of the most stable dimer is predicted to be -31.85kJ/mol at the MP4/6-31G^**//MP2/6-31G^** level.The energy barriers of the Walden conversion for -NH2 group are 19.7kJ/mol and 18.3kJ/mol for monomer and the most stable dimer,respectively.The molecular interaction makes the internal rotation around N1-N2 even more difficult.The thermodynamic properties of nitroamine and its dimers at different temperatures have been calculated on the basis of vibrational analyses.The change of the Gibbs free energy for the aggregation from monomer to the most stable dimer at standard pressure and 298.2 K is predicted to be 14.05kJ/mol.     

硝仿肼离子对相互作用的密度泛函理论研究

用密度泛函理论(DFT)方法,在B3LYP/6-31+G^**水平下,求得硝仿肼离子对体系势能面上2种全优化构型.经基组叠加误差(BSSE)和零点能校正,求得离子对最大相互作用能为-420.03kJ/mol,肼和硝仿离子化所需能量可由该值得到完全补偿.离子对间键的主要贡献为库仑作用,但键鞍点上的电子密度值表明共价作用也有显著的贡献.基于统计热力学求得相关体系的热力学性质,298.2K时由自由离子形成最稳定离子对的最大焓变和最大自由能变化分别为-419.72和-376.61kJ/mol     

Theoretical Study on the Intermolecular Interactions of Tetrazole Dimers

1 INTRODUCTION Tetrazole and its derivatives are widely applied in the fields of agriculture, biology, chemistry, phar- macology and photographic technology, and they play significant roles in the science and technology as well as national defence[1]. In the past, the res- earches were focused on the molecular geometries, electronic structures, IR, thermodynamic properties, tautomerization, pyrogenation and sensitivity of tetrazole compounds[1～5]. However, study of tetra- zole dimers ha…     

3,6-二氨基-1,2,4,5-四嗪二聚体分子间相互作用的理论研究

在DFT-B3LYP/6-31G(d)水平下,求得3,6-二氨基-1,2,4,5-四嗪二聚体势能面上3种优化几何构型和电子结构。经基组叠加误差(BSSE)和零点能(ZPE)校正,求得分子间最大相互作用能为-38.88kJ/mol。电荷分布与转移分析表明,二子体系间的电荷转移很少,但接触点上氮原子和氢原子电荷变化比较大。由自然键轨道(NBO)分析揭示了分子间相互作用的本质。对优化构型进行振动分析,并基于统计热力学求得200.0~800.0 K温度范围从单体形成二聚体的热力学性质变化,发现二聚主要由强氢键所贡献,二聚过程在较低温度或常温下能自发进行。     

Ab initio Studies on Intermolecular Interaction of Formamide and Hydroxyacetonitrile Dimers

The structures, the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile(HAN) dimers have been studied by means of the self-consistent ab initio Hartree-Fock and the second-order Mφller-Plesset correlation energy correction methods. The counterpoise procedure was used to check the basis set superposition error(BSSE) of the binding energies. There exist cyclic structures in a formamide dimer(Ⅰ), a HAN dimer(Ⅱ) and their heterodimer(Ⅲ). The corrected binding energies for dimers Ⅰ, Ⅱ and Ⅲ are respectively -45.53, -45.83 and -43.89 kJ/mol at the MP2/aug-cc-p VDZ//HF/aug-cc-p VDZ level. The change of the Gibbs free energies(ΔG) in the process of Ⅰ Ⅱ→2Ⅲ was predicted to be -2.74 kJ/mol at 298.15 K. Dimer Ⅲ can be spontaneously produced in the mixture of formamide and HAN, which is in agreement with the experimental fact that most cyanohydrins are capable of interacting with dipeptide cyclo-His-Phe(CHP).     

Theoretical Studies on Intermolecular Interactions of 4-Amino-5-nitro-1,2,3-triazole Dimers

1 INTRODUCTION Triazole, a five-membered heterocyclic compound with three nitrogen atoms, is an important interme- diate product of medicine and chemical industry as well as insecticide [1]. Due to its small volume and high nitrogenous density, triazole holds more and more attraction for the material researchers, espe- cially the researchers of high-energy insensitive explosive. It is reported that its nitro and amino deri- vatives are a sort of important high-energy mate- rials[2]. Previ…     

NTO二聚体分子间相互作用的理论研究

在DFT-B3LYP/6-311＋＋G**水平上求得NTO二聚体势能面上六种优化构型和电子结构. 经基组叠加误差(BSSE)和零点能(ZPE)校正, 求得分子间最大相互作用能为－53.66 kJ/mol. 二子体系间的电荷转移很少. 由自然键轨道分析揭示了相互作用的本质. 对优化构型进行振动分析, 并基于统计热力学求得200.0～800.0 K温度范围从单体形成二聚体的热力学性质变化. 发现二聚主要由强氢键所贡献, 但结合能大小并不为氢键所完全决定. 二聚过程在较低温度或常温下能自发进行.