相对稳定性

The comparative stability of the aggregates cannot, however, be accounted for—as the statisticians occasionally seem to be inclined to do—by the "law of large numbers" or the mutual compensation of random changes.

然而，总量的相对稳定性并不能—像统计学家们偶尔所做的那样--用"大数定律"或随机变动的相互抵消来解释。要对付的因素的个数还没有大到偶然因素产生稳定性的程度。

On the basis of the relative magnitude of their standard free energy of formation.

根据标准生成自由能的相对大小，从理论上求得异构体的相对稳定性顺序。

In addition, NBO analysis shows that it is hyperconjugation rather than repulsive forces that plays a key role in the relative stabilities of isomers.

此外， 通过NBO方法分析了分子的超共轭作用和立体排斥能对异构体稳定性的影响，结果表明超共轭作用是影响各异构体构型相对稳定性的主要因素。

The structural parameters of PNHAAs, such as the the maximum N-NO2 bond length, the least N-N Mulliken population, the least negative charge on the nitro group (QNO2) and OB100, were studied to predict their relative stability or sensitivity (the easiness for initiating a detonation, high sensitivity means low stability).

通过研究PNHAAs的结构参数，如N-NO2最大键长、N-NO2键的最小Mulliken集居数、-NO2所带最小负电荷、氧平衡，预测了10个标题物的相对稳定性或感度(起爆的难易程度。感度越高，化合物的稳定性越低)。

The DFT (B3LYP/6-31 + G) method was used to study the relative stabilities and probable proton transfer in isolated and monohydrated 2,4-dithiothymine molecules in gas phase. The effects of water on relative stabilities and the rate of the proton transfer were analysed. The results indicate that only one tautomer for 2,4-dithiothymine can exist in gas phase.

采用密度泛函方法在B3LYP/6-31+G水平上研究了2，4-二硫基胸腺嘧啶孤立分子和水合物的异构体的相对稳定性和可能的质子迁移反应，分析了水分子的参与对 2，4-二硫基胸腺嘧啶异构体的相对稳定性和质子迁移速率的影响。

In this thesis,the AM1,MNDO,MINDO/3(mainly AM1)and INDO/S-CI semiempirical MO methods were used toinvestigate the excited-state intramolecular protontransfer reactions of salicylic acid derivatives—salicylic acid,methyl salicylate,salicylaldehyde,o-hydroxyaceto-phenone,salicylamide and 3-hydroxy-picolinamide (6 conformers and 2-3 anion species);2-(2'-hydroxy-5' methylphenyl) benzotriazole(4 conformers),2-(2' hydroxyphenyl) benzimidazole (3 conformers and 3anion species),Bis-2,5-(2-benzoxazolyl)hydroquinone(3 conformers),2-(2'-hydroxyphenyl)benzothiazole(2conformers) and 7-azaindole dimer (2 conformers).Theinvestigations were described as follows.Geometry optimization,relative stability andhydrogen bonding energy First,for sylicylic acid derivative molecules,the AM1,MNDO and MINDO/3 methods were used toinvestigate ground-state geometry optimization,energies,relative stabilities and hydrogen-bondingenergies on the five kinds of the molecules(designing 6 conformers and 2-3 anion species).Comparing with experimental data,the optimizedgeometry,the order of stability,the hydrogen-bonding energies and the distances between O-O in O-H..O hydrogen bonds by AM1 method were in agreementwith the experimental data,however,the C-C bondlengths optimized by MNDO and MINDO/3 were longer,C-O and O-H bond lengths were shorter;for C-N bondlengths,the results opitimized by MNDO method werethe same as those by AM1 method,nevertheless the C-Nbond lengths given by MINDO/3 method were muchshorter.For some sylicylic acid derivatives(e.g.methyl salicylate,salicylamide),the order ofstabilities on the conformers given by MNDO andMINDO/3 methods were not in agreement with theexisting conformers deduced by experimental methods,and the hydrogen bonding energies calculated by MNDO.and MINDO/3 methods were smaller.Second,the studyon the other systems found that the optimizedgeometry of the proton-transfered product with INDOmethod could not be obtained,only could theoptimized geometry of reactant be obtained,and thecalculated hydrogen bonding energies were greater.Many results of calculation indicated that the studyon the excited-state intramolecular proton transferreaction system using AM1 method was suitable andreliable.

本论文用AM1、MNDO、MINDO/3（主要是AM1）和INDO/S-CI半经验分子轨道方法对水杨酸衍生物系列——水杨酸、水杨酸甲酯、水杨醛、O-羟基乙酰苯酮、水杨酰胺和3-羟基吡啶酰胺（6种异构体和2-3种阴离子）；2-（2'-羟基-5'-甲基苯基）苯并三〓唑（4种异构体）；2-（2'-羟基苯基）苯并咪唑（3种异构体和3种阴离子）；2，5-二间氮杂氧茚氢醌（3种异构体）；2-（2'-羟基苯基）间〓杂硫茚（2种异构体）和7-〓吲哚二体（2种异构体）的激发态分子内质子转移反应在以下几个方面进行了较系统的理论研究：几何构型优化和相对稳定性及氢键能首先以水杨酸衍生物系列分子为例，用AM1、MNDO和MINDO/3方法考察了5种分子（每种分子设计6种异构体和2-3种阴离子）的基态几何构型优化，能量、相对稳定性和氢键能计算，通过和实验数据进行比较，AM1方法给出的优化几何构型、稳定性次序、氢键能和O—H。。。O氢键的0—0距离与实验数据吻合最好，MNDO和MINDO/3方法优化的C-C键长偏长，C-O键和O-H键长偏短；对于C-N键长，MNDO和AM1优化结果差别不大，而MINDO/3给出了过短的C-N键长，MNDO和MINDO/3方法给出的有些水杨酸衍生物分子（如水杨酸甲酯和水杨酰胺）异构体的稳定性次序和实验上推测的可存在异构体结果不一致，MNDO和MINDO/3方法给出的氢键能偏低，对其他体系的研究发现INDO方法常常不能得到质子转移产物的优化几何构型，只能得到反应物的优化构型，并且估算的氢键能偏高，大量的计算结果表明AM1方法对本论文研究的激发态分子内质子转移反应体系是适宜和可靠的。

Our calculated results show that the relative stability of the isomers depends on the level of theory used: in the framework of DFT, Au10 trends to form planar structures, while the MP2 calculations show that the three-dimensional isomers are energetically more favorable. Based on the present results, Au10 may be conjecturably a critical species of gold clusters which bridges the planar structures and three-dimensional ones.

计算结果表明Au10团簇异构体的相对稳定性明显依赖所使用的理论方法和泛函，密度泛函结果显示Au10倾向于采用平面结构，且不同的泛函给出异构体的相对稳定性次序也不相同，而MP2计算则显示三维空间结构的Au10团簇更稳定， Au10可能是金团簇从二维结构到三维结构演化的一个临界点。

Analyzed the relative stability and isomerization, it was found that Ni3BPsuperscript (3 was thermodynamically the most stable one. In addition, Ni3BPsuperscript (1, Ni3BPsuperscript (1 with singlet state and Ni3BPsuperscript (3, NiPsuperscript (3 with triplet state are kinetically stable ones.

分析各异构体的相对稳定性及异构化过程得出：Ni3BP上标(3是单、三重态中热力学最稳定的异构体；单重态的Ni3BP上标(1、Ni3BP上标(1和三重态的Ni3BP上标(3、Ni3BP上标(3具有一定的动力学稳定性。

The relative stabilities and probable proton transfer in isolated and monohydrated 2-hydroxyimidazole molecules have been studied in gas phase using ab initio (MP2/6-31＋G *) method.

采用从头算方法在MP2/6-31＋G*水平上研究了2-羟基咪唑分子在孤立分子和一水合物的异构体的相对稳定性和可能的质子迁移反应，分析了一个水分子的参与对2-羟基咪唑分子异构体的相对稳定性和质子迁移速率的影响，采用Monte Carlo模拟方法研究了反应体系在水溶液中反应的溶剂化效应。

The stability of PBPTH congeners was theoretically proposed based on the relative magnitude of their .

根据 的相对大小，从理论上求得异构体的相对稳定性顺序。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。