共查询到20条相似文献,搜索用时 62 毫秒
1.
运用DFT-w B97/6-31+G**方法对23种1,2,4,5-四嗪衍生物的几何结构、自然键轨道(NBO)和生成焓(EOF)进行研究,并在此基础上运用Kamlet-Jacobs方程估算衍生物的爆轰性能,得到其爆速在6.69~9.37 km/s之间;基于统计热力学,求得部分标题化合物在200~800 K温度范围内的热力学性质,随温度T升高,热容Cp、熵Sm及焓Hm逐渐增大。根据最小键级理论,C-R(取代基)键和N-R键可能是1,2,4,5-四嗪衍生物高温裂解的热引发键。综合分析,基团-NO2、-N3和-N=N-有助于提高四嗪衍生物的生成焓和爆轰性能,3,6-二硝基-1,2,4,5-四嗪和3,6-二偶氮基-二硝基-1,2,4,5-四嗪从能量、爆轰性能上可以作为高能量密度材料候选物。 相似文献
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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. 相似文献
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选取人教版高中教材《化学1》中10个实验,对北京市6所中学的364名高一学生进行调查研究,结果表明:学生对化学实验的理解水平总体不高;关联结构均值显著低于单一/多元结构和拓展抽象结构;3个维度之间呈显著正相关;学生对无机非金属元素一章的实验的理解水平较低;对溶液配制实验和金属钠的相关实验的理解水平较高。男生和女生在化学实验理解程度上没有显著性差异。基于调查结果提出实验教学建议。 相似文献
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M0,±6(M=Os,Ir,Pt)团簇结构与性质的密度泛函理论研究 总被引:1,自引:1,他引:0
采用密度泛函理论(DFT)中的杂化密度泛函(B3LYP)方法,在LANL2DZ基组水平上对M06,±(M=Os,Ir,Pt)团簇的各种可能构型进行了几何结构优化,得出各团簇的最稳定构型,并对其能量、振动频率、热力学性质、核独立化学位移(NICS)和极化率进行了理论研究.结果表明,M06,±(M=Os,Ir)团簇的基态都是三棱柱结构,Pt-6团簇的基态是平面三角形结构;M06,±(M=Os,Ir,Pt)团簇生成焓都为负值,热力学上是稳定的;NICS值都为负值,表明M06,±(M=Os,Ir,Pt)团簇都具有芳香性,其中Os6-团簇的芳香性最强;从光谱分析来看,Os6的IR和Raman谱的较强吸收峰的个数最多,Ir6的IR和Raman谱的最强吸收峰都只有一个,IR最强吸收峰在137.O和143.5 cm-1之间,Raman谱最强的吸收峰位于169.5 cm-1处;Pt6的IR和Raman谱的最强吸收峰分别位于50.2和194.7 cm-1处. 相似文献
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采用密度泛函理论(DFT)中的杂化密度泛函(B3LYP)方法,在LANL2DZ基组水平上对M06,±(M=Os,Ir,Pt)团簇的各种可能构型进行了几何结构优化,得出各团簇的最稳定构型,并对其能量、振动频率、热力学性质、核独立化学位移(NICS)和极化率进行了理论研究.结果表明,M06,±(M=Os,Ir)团簇的基态都是三棱柱结构,Pt-6团簇的基态是平面三角形结构;M06,±(M=Os,Ir,Pt)团簇生成焓都为负值,热力学上是稳定的;NICS值都为负值,表明M06,±(M=Os,Ir,Pt)团簇都具有芳香性,其中Os-6团簇的芳香性最强;从光谱分析来看,Os6的IR和Raman谱的较强吸收峰的个数最多,Ir6的IR和Raman谱的最强吸收峰都只有一个,IR最强吸收峰在137.0和143.5 cm-1之间,Raman谱最强的吸收峰位于169.5 cm-1处;Pt6的IR和Raman谱的最强吸收峰分别位于50.2和194.7 cm-1处. 相似文献
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采用B3LYP方法和6-311G(d, p)基组对CH3S及其氧化后继物CH3SO与Oy (y=1, 2, 3)反应形成酸雨的微观机理进行了理论研究. 对反应势能面上的各驻点进行几何构型全优化. 振动分析和IRC计算证实了中间体和过渡态的真实性和相互连接关系. 找到了7条生成SO2的反应途径, 其中CH3S与O直接反应得到产物CH3和SO最容易进行; CH3S先与O3反应, 其产物再与O3反应得到CH3SO2, CH3SO2最后分解得到CH3S和SO2较容易进行, 其它的反应较难进行. 相似文献
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采用密度泛函理论(DFT)方法研究了一系列超碱金属复合物Al7X0/-(X=F,Cl,Br,I)的几何结构及二阶非线性光学(NLO)性质.结果表明,不同卤素的连接对Al0/-7簇的几何构型影响均很小.计算得到Al7X和Al7X-体系的垂直电离能(VIE)均低于Cs原子的第一电离势(IP=3.90 eV),表明这些体系具有超碱金属的性质,可称其为超碱金属.此外,采用CAM-B3LYP,M06-2X和PBE0等3种泛函计算了该体系的非线性光学性质,结果显示,上述体系均具有较大的第一超极化率(β0),其中Al7I-的β0值为21679 a.u.,是已知超碱金属复合物BLi6F(11459 a.u.)的1.9倍.值得注意的是,该类体系的第一超极化率随着卤素电负性的减小而增大,即Al7F0/-相似文献
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采用密度泛函B3LYP方法, O和N用6-311+G*基组, Au+用赝势基组(8s7p6d)/[6s5p3d], 研究了Au+(1S, 3D)离子和N2O(1Σ+)分子的反应机理. 报道了在基态单重态和激发三重态势能面上各反应物、中间体和过渡态的构型特征及能量. 结果表明, 两个主反应通道Au+(1S)+ N2O(1Σ+)→1NA-Complex-1→1NA-TS1→1NA-Complex-2→1NA-Crossing→[3OAuNN]+和Au+(1S)+ N2O(1Σ+)→1NB-Complex→1NB-Crossing→[AuNN(1Σ+)]++O(3P)都需经过反应交叉势能面, 出现“系间窜越”. 用内禀坐标单点计算垂直激发态的方法确定了势能面交叉点, 并用含时密度泛函TD-B3LYP方法进一步探讨了自旋翻转机理. 相似文献
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采用B3LYP方法和6-311G(d, p)基组对CH3S及其氧化后继物CH3SO与Oy (y=1, 2, 3)反应形成酸雨的微观机理进行了理论研究. 对反应势能面上的各驻点进行几何构型全优化. 振动分析和IRC计算证实了中间体和过渡态的真实性和相互连接关系. 找到了7条生成SO2的反应途径, 其中CH3S与O直接反应得到产物CH3和SO最容易进行; CH3S先与O3反应, 其产物再与O3反应得到CH3SO2, CH3SO2最后分解得到CH3S和SO2较容易进行, 其它的反应较难进行. 相似文献
11.
Li Yincheng 《化学物理学报(中文版)》2003,16(1):25-29
The parameters of strong detonation for Nitromethane (NM) were calculated with the two-phase Repellent-Translation Equation of State(two-phase R-T EOS).The results are quite consistent with the data of quasi-steady strong detonation experiment in NM that contain velocities, pressures and temperatures. This not only tested the calculation method, but also the ZND theory of detonation and the two-phase R-T EOS again. Furthermore, the experiment methods were supported. The strong detonation parameter calculation method with the constant-kequation of state was conditionally confirmed. 相似文献
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从硬球微扰理论推导马丁-侯状态方程 总被引:4,自引:0,他引:4
从Barher-Henderson的硬球微扰理论出发,运用幂级数形式的径向分布函数和分段的势能函数导出马丁-侯状态方程,推导过程中导出了一种理论式,计算P-V-T性质的精确度与马丁-侯原式相当,理论式的常数与分子微观参数有确定的函数关系。 相似文献
13.
Using three kinds of experimental data (pc, Vc and Tc at the critical state or Ps, Vsv and VsL at different temperatures for saturation data) three parameters of the EOS may be directly determined and the temperature dependence of the parameters may be established from thermodynamic conditions of vapour-liquid critical point or vapour-liquid phase equilibria respectively. The principle was demonstrated on the BACK EOS. Examples of argon and n-alkanes were used to demonstrate the idea. It was found, that there are two parameter sets of the BACK equation that satisfy the critical or saturation conditions for certain pure compounds. The BACK equation is able to reproduce experimental Zc values for compounds above Zc = 0.2764 (that is, for argon, methane, ethane), but it is improper for higher alkanes. In case of n-alkanes we found that there is no simple function for T dependence of BACK parameters. Parameter values obtained in the way demonstrated may be useful to give initial values for parameter estimation from experimental (e.g., VLE) data. 相似文献
14.
张秉坚 《高等学校化学学报》1995,16(9):1440-1444
提出在Barker与Henderson的压缩性近似推导中,相邻壳层之间的分子数应该相关,导出了相关系数和改进的二级微扰项,提高了高级微扰项在较高密度区的准确性。对二级以上的高级微扰项采用Barker与Henderson的近似方法,得到一个简单的微扰理论表达式,以硬球势为参考势,方阱势为微扰势,用一新的级数形式的径向分布函数导出了自由能、内能、比热、压缩因子的级数表达式。其四项截断式的计算结果与MC、MD计算机模拟值符合较好。 相似文献
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Ammonia borane (AB) is used as a combustion agent to improve the properties of high explosives. The detonation velocity (Dv) and detonation pressure (P) of raw high explosives and of samples containing AB were calculated and compared. The detonation properties, impact sensitivities, thermal sensitivities, and thermal decomposition characteristics of high explosives containing AB were also measured. The results indicated that when the AB content was 20 wt‐%, the optimal detonation velocity and detonation pressure were achieved. Both the detonation velocity and detonation pressure of the high explosives containing AB were clearly increased compared with those of the raw high explosives. Moreover, the detonation velocities of high explosives containing AB were 7078 to 7423 m · s–1 and their density ranged from 1.570 to 1.589 g · cm–3. The detonation pressure ranged from 34.5 to 37 GPa and the average heat of detonation was 6688 J · g–1. Furthermore, the impact and thermal sensitivities were 170 cm and 613 K, respectively, whereas a slight change occurred in the thermal decomposition characteristics. These results suggest that AB can serve as a powerful combustible agent in energetic materials and improve the detonation properties and sensitivities of high explosives. 相似文献
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In 1873 van der Waals1 proposed a two-parameter cubic equation of state (EOS), which provides a rather clear physical picture of molecular interactions in real fluids. Because of its simplicity, it soon was widely used. Other famous equations of state, such as PR2, Soave3, have been proposed since then. But all these equations are not accurate enough when applied to liquid phase.The trend of modeling the properties of fluids is that a single equation of state can be applied to both vapor an… 相似文献
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The relationship between detonation velocity and the elemental composition of components of aluminized explosives are assessed through quantitative structure-property relationship (QSPR). Here, two new reliable, simple models are proposed for estimating aluminized explosives detonation heat and velocity based on molecular structure by applying QSPR. In this methodology it is assumed that these two detonation parameters can be presented as a function of elemental composition, density and several structural parameters. This new correlation of heat detonation has determination coefficient of 0.930, root mean square deviation (RMSD) of 324.4 and average absolute deviation (AAD) of 446kJ · kg–1 for 36 aluminized explosives with different molecular structures as the training set. The predictive power of this new correlation is checked through a cross validation method. Statistical parameters reveal relatively good result for this correlation. Also, the determination coefficient of detonation velocity for the other new model is 0.960 and it has 151.1 (RMSD) and 107.9 m · s–1 (AAD) for 42 aluminized explosives with different molecular structures as training set. Reliability and validity of new correlation investigated (Q2Ext = 0.948, Q2LOO = 0.938, and Q2LMO = 0.937). The good ability of this new model for prediction detonation velocity of aluminized explosives are confirmed. 相似文献
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In this brief review article some aspects of the thermodynamics of polymer mixtures are discussed, mainly based on the author's research. The studies of poly (methyl methacrylate)/chlorinated polyethylene (CPE), poly (butyl acrylate)/CPE and CPE/CPE (different chlorine content) mixture verify the "dissimilarity" and "similarity" principles for predicting miscibility of polymer mixtures. The sign of heat of mixing of oligomeric analogues is not sufficient in predicting the miscibility. The Flory equation of state theory has been applied to simulate the phase boundaries of polymer mixtures. The empirical entropy parameter Q_(12) plays an important role in the calculation, this reduces the usefulness of the theory. With energy parameter X_(12)≠0 and Q_(12)≠0 the spinodals so calculated are reasonable compared to experiments. A hole model was suggested for the statistics of polymer mixtures. The new hole theory combines the features of both the Flory equation of state theory and the Sanchez lattice fluid theory and can be reduced to them under some conditions. 相似文献
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炸药爆轰合成纳米石墨的红外光谱研究 总被引:2,自引:0,他引:2
石墨是碳材料中最常见的结晶状态,它具有耐高温、抗腐蚀、自润滑、无毒及价格低廉等特点,广泛应用于润滑剂和添加剂等方面[1].由于高纯纳米石墨粉在某些高新技术领域中有较好的应用前景,近些年来得到开发和应用,如制成复合导电材料、吸波材料及储氢材料等[2].以前有学者用纳米金刚石粉加热相转变[3]和高能球磨[4,5]的方法制备了纳米石墨,在制备碳纳米管时也有石墨的纳米粒子生成[6].但用这几种方法制备纳米石墨,既费时又消耗较大能量,成本非常高. 相似文献