微扰论

摘要： 量子力学中用来求问题的近似解方法,通常是从简单问题的精确解出发来求较复杂问题的近似解.体系的哈密顿算符不是时间的显函数的情况,讨论的是定态问题.用定态微扰论计算,具有一定电偶极矩的刚性转子绕中心在一平面内转动,在转动平面内存在电场强度时能量的修正.

摘要： 采用QM与MM组合的ONIOM方法,对标题反应进行了研究.结构分析表明:SWBNNT(硼氮纳米管)(5,5)的限制致缬氨酸分子骨架明显形变,同时SWBNNT(5,5)也发生了形变.计算表明:以氨基氮为质子转移桥梁的旋光异构是优势反应通道.缬氨酸限域在SWBNNT(5,5)时,旋光异构决速步的内禀能垒是318.41 kJ·mol-1;缬氨酸限域在SWBNNT(6,6)时,质子迁移与羟基旋转同步与分步进行的旋光异构决速步的内禀能垒分别是306.42和306.93 kJ·mol-1.均比裸反应优势通道的决速步能垒268.93 kJ·mol-1显著升高.缬氨酸限制在SWBNNT(7,7)时,旋光异构决速步的内禀能垒是262.81 kJ·mol-1,与裸反应相差无几.结果表明:SWBNNT(5,5)和SWBNNT(6,6)的限域对缬氨酸旋光异构具有明显的负催化作用.

摘要： the energy level distribution of two-particle system under the action of external magnetic field is given by means of accurate solution and perturbation theory. The research results show that under the condition of weak magnetic field, the total spin S is a conserved quantity, and the s1 and s2 is not conserved. Under the con‐dition of strong magnetic field, the s1z, s2z and Sz are conserved quantities. In general, only SZ is conserved quan‐tities, the s1z , s2z and S2 are not conserved. The same SZ and different S states may be coupled to form the energy Eigen states. In the limit of strong or weak magnetic field ( even without magnetic field) , there is a degeneracy of energy level.%通过精确求解和微扰理论的方法给出了外磁场作用下双粒子体系的能级分布,研究结果表明在弱磁场条件下,总自旋S为守恒量, s1和s2则不守恒;在强磁场条件下, s1z , s2z , Sz均为守恒量;在一般情况下,仅Sz为守恒量, s1z , s2z及S2均不守恒, Sz相同而S不同的状态有可能发生耦合而形成能量本征态;在强磁场极限和弱磁场(以至无磁场)极限,均出现能级对Sz的简并.

摘要： 通过对非简并的含微扰三能级系统的研究,详细讨论不同位置的微扰矩阵元对能量修正的影响,进而总结相应的规律.

摘要： 在MP2/6-311 ++G(2df,pd)//B3LYP/6-31 +G(d,p)双理论水平,采用自洽反应场(SCRF)理论的smd模型方法,对标题反应进行了研究.反应通道研究表明:水环境下缬氨酸的旋光异构可以在3个通道a、b和c实现,分别是质子以水分子簇为媒介以氨基氮、羰基氧和羧基为桥梁,从α-碳的一侧迁移到另一侧;水分子辅助羟自由基抽氢致缬氨酸损伤发生在a通道.势能面计算表明:2个和3个水分子簇作氢迁移媒介时,水分子簇对旋光异构反应的氢迁移过程有极好的催化作用,使反应能垒相对裸反应大幅降低,水溶剂效应在a通道有较好的助催化作用,对b和c通道影响不大.水分子辅助羟自由基抽氢致缬氨酸损伤气相反应能垒较低,水溶剂效应对此反应有较大的阻碍作用.%The mechanism of optical isomerization of valine molecules with dual-hydrogen bonds between amino and carboxyl groups and the damage induced by hydroxyl radicals in water environment were stud-ied by using MP2/6-311 ++G(2df,pd)//B3LYP/6-31 +G(d,p)dual-theory and SMD model method for self consistent reaction field(SCRF)theory.The study of reaction channels showed that there were three channels a,b and c in the optical isomer reaction of valine in water environment.Using water cluster as medium,the protons transfered from one side of the α-carbon to the other side with N atom of amino group,O atom of carbonyl group and carboxyl group as bridges.The hydrogen abstraction reaction which damaged the valine molecules happened in channel a,and the water molecules were assistants. The potential energy surface calculation showed that when two or three water clusters were used as hydro-gen transport medium,they acted a good catalytic action on the process of hydrogen-transfer of Optical I-somerization,and reduced the barrier of reaction vs naked reaction.Water solution effect had good cata-lytic activity in channel a,but catalytic activities were not obvious in channel b and c.The reaction bar-rier of hydrogen abstraction reaction which damaged the valine molecules with water molecules as assis-tants was low.The water solution effect has a big impediment effect on this reaction.

摘要： 基于MP2/6-311++G(2df,pd)//B3LYP/6-31+G(d,p)双理论水平,用自洽反应场(SCRF)理论的SMD模型方法,考察水环境下氢氧根水分子簇催化缬氨酸旋光异构及羟自由基致其损伤机理.结果表明:缬氨酸的旋光异构可在2个通道a和b实现,通道a为氢氧根水分子簇与α-H和氨基通过氢键作用形成底物,氢氧根抽取α-H后,α-C在另一侧抽取水分子的H;通道b为氢氧根水分子簇与 α-H和羰基通过氢键作用形成底物,氢氧根抽取α-H后,α-C在另一侧抽取水分子的H,通道b中的水分子辅助羟自由基抽取α-H可致缬氨酸损伤;水液相环境下,构象Val-1(氨基羧基间为单氢键)和构象Val-2(氨基羧基间为双氢键)在通道a旋光异构的决速步骤能垒分别为60.57,65.24 kJ/mol,在通道b旋光异构的决速步骤能垒分别为56.76,64.11 kJ/mol,羟自由基水分子簇致缬氨酸在通道b的损伤为温和的放热反应.

摘要： 在MP2/6-311++G(2df,pd)//B3LYP/6-31+G(d,p)双理论水平,采用自洽反应场(SCRF)理论的SMD模型方法,对标题反应进行了研究.反应通道研究表明:裸环境下缬氨酸的旋光异构可以在3个通道a、b和c实现,a和b分别是α碳上的质子按分步和协同机理以氨基氮为桥迁移,c是α碳上的质子以羰基氧为桥迁移,水环境下只有a和c通道;羟自由基抽氢致缬氨酸损伤只在a通道.势能面计算表明:a通道具有优势,2个和3个水分子簇作氢迁移媒介时,水分子簇对旋光异构反应有极好的催化作用,使反应能垒相对裸反应大幅降低,水溶剂在a通道有较好的助催化作用.水分子辅助羟自由基抽氢致缬氨酸损伤气相反应能垒较低,水溶剂效应使损伤能垒大幅提升.

摘要： 采用密度泛函理论的B3LYP方法和微扰理论的MP2方法,研究两种最稳定构型的蛋氨酸分子(Met)基于氨基作为质子迁移桥梁的旋光异构反应.结果表明:基于氨基作为质子迁移桥梁的蛋氨酸分子旋光异构反应有2条通道a和b;构型1的主反应通道为通道a,决速步骤为第1基元反应,自由能垒为264.2 kJ/mol,由质子从手性C直接向氨基N迁移的过渡态产生;构型2的主反应通道也为通道a,决速步骤为第2基元反应,自由能垒为266.1 kJ/mol,由羧基异构后质子从手性C向氨基N迁移的过渡态产生;两种构型的Met分子旋光异构速控步骤的反应速率常数分别为3.04×10-34,1.41×10-34 s-1.%We studied the optical isomerism reaction of two kinds of the most stable configurations of methionine molecules based on amino group as proton transfer bridge by using the B3LYP method of density functional theory and the MP2 method of perturbation theory.The results show that there are two channels a and b in the optical isomerism reaction of methionine molecules based on amino group as proton transfer bridge.The dominant reaction channel of the configuration one is channel a,the rate-determining step is the first elementary reaction,and the free energy barrier is 264.2 kJ/mol that is generated by the transition state of proton transfer from the chiral C to the amino N.The dominant reaction channel of the configuration two is the channel a,the rate-determining step is the second elementary reaction,and the free energy barrier is 266.1 kJ/mol that is generated by the transition state of proton transfer from the chiral C to the amino N after carboxyl group isomerism.The reaction rate constants of the optical isomerism rate-determining step of two configurations of methionine molecules are 3.04×10-34,1.41×10-34 s-1,respectively.

摘要： The title reaction mechanism was explored by using the B3LYP density functional theory,the MP2 method of perturbation theory and smd model method of self consistent reaction field theory.The study of reaction channels showed that there are two channels a,b in the chiral transition reaction,and in the one the proton is transferred from one side to the other of chiral carbon with only the amino as a bridge,in the other with carbonyl and amino N as the bridge successively.The molecular structure analysis showed that the seven-ring structure in the transition state aTS2·2H2O is almost coplanar and each hydrogen bond angles of the seven-ring structure approach straight angle.Calculations of potential energy surface pointed out that the channel a is the dominant reaction channel and the free energy barrier of the rate-determining step is 249.5 kJ·mol-1,which is caused by the transition state with proton migration from chiral carbon to amino nitrogen.Moreover,with consideration of two water molecules as H transfer media and with inclusion of the water solvation effect of the continuous medium model,,the free energy barrier of the rate-determining step is reduced to 113.2 kJ·mol-1 and the reaction rate constant is 5.85×10-8 s-1,and the water solvation effect enables the energy barrier of the amino heterogeneous reaction increased from 13.4 kJ·mol-1 to 19.3 kJ·mol-1.Therefore,water solvation effect can hinder the heterogeneous reaction of non proton transfer,and the interaction of the catalytic action of water molecules and water solvation effect can cooperatively reduce the proton transfer reaction energy barrier to a large degree.%采用密度泛函理论的B3LYP方法、微扰理论的MP2方法和自洽反应场理论的smd模型方法,对标题反应进行了研究.反应通道研究发现:标题反应有2条通道a和b,分别是质子H只以氨基和以羰基与氨基顺次为桥,从手性碳的一侧迁移到另一侧.结构分析表明:过渡态aTS2·2H2O分子内的7元环结构基本共面,7元环结构的各个氢键角接近平角.势能面计算表明:a是主反应通道,决速步自由能垒为249.5 kJ·mol-1,由质子从手性碳向氨基氮迁移的过渡态产生;2个水分子作H迁移媒介,同时考虑连续介质模型的水溶剂化效应时,决速步自由能垒降到113.2 Kj·mol-1,反应速率常数为5.85×10-8 s-1;水溶剂化效应使氨基异构反应的能垒从裸反应的13.4 Kj·mol-1升高到19.3 Kj·mol-1.结果表明:水溶剂化效应对非质子迁移的异构反应具有阻碍作用;水分子的催化和水溶剂化效应的共同作用,使质子从手性碳向氨基迁移反应的能垒大幅度降低.

摘要： 在宏观世界向微观世界过渡时,由于宏观理论与微观理论存在矛盾,量子力学也就随之产生了。在解决它们之间的矛盾时,许多物理规律和物理概念被一一揭示出来。可以用本征方程或是矩阵法求系统的本征值。在此文章中,我们是用本征方程来求系统的本征值以及本征态的,常用的系统模型是Jaynes-Cummings模型。解本征方程过程中,量子化物理特性可以很好的看到,即,本征值是不连续的。然而此文中,我们的系统是在原来的二能级系统基础上,加一个外部弱驱动。使用微扰理论方法,求系统的本征值以及本征态。

摘要： 真正解决重整化能标及重整化方案不确定性最大共形原理——PMC。可以选择任意初始重整化能标、重整化方案完成微扰论计算;但经过PMC能标设定步骤之后，最终获得的微扰表达式与初始重整化能标、重整化方案的选择无关。

摘要： 该文提出了同轴波导大回旋半径电子注来用纵向静磁场与径向静电场聚焦，实现回旋潘尼管的设想。用扰动法严格求解了在高频场（TEmn模或TMmn模）作用下，电子的三维运动。详细地分析了回旋同步不稳定性及径向谐振不稳定性、用正规模方法求得了扰动电流密度的一般表达式。得到了采用薄电子注时的色散方程。（本刊录）

摘要： 该文提出了同轴波导大回旋半径电子注来用纵向静磁场与径向静电场聚焦，实现回旋潘尼管的设想。用扰动法严格求解了在高频场（TEmn模或TMmn模）作用下，电子的三维运动。详细地分析了回旋同步不稳定性及径向谐振不稳定性、用正规模方法求得了扰动电流密度的一般表达式。得到了采用薄电子注时的色散方程。（本刊录）

摘要： 该文提出了同轴波导大回旋半径电子注来用纵向静磁场与径向静电场聚焦，实现回旋潘尼管的设想。用扰动法严格求解了在高频场（TEmn模或TMmn模）作用下，电子的三维运动。详细地分析了回旋同步不稳定性及径向谐振不稳定性、用正规模方法求得了扰动电流密度的一般表达式。得到了采用薄电子注时的色散方程。（本刊录）

摘要： 该文提出了同轴波导大回旋半径电子注来用纵向静磁场与径向静电场聚焦，实现回旋潘尼管的设想。用扰动法严格求解了在高频场（TEmn模或TMmn模）作用下，电子的三维运动。详细地分析了回旋同步不稳定性及径向谐振不稳定性、用正规模方法求得了扰动电流密度的一般表达式。得到了采用薄电子注时的色散方程。（本刊录）

摘要： 该文提出了同轴波导大回旋半径电子注来用纵向静磁场与径向静电场聚焦，实现回旋潘尼管的设想。用扰动法严格求解了在高频场（TEmn模或TMmn模）作用下，电子的三维运动。详细地分析了回旋同步不稳定性及径向谐振不稳定性、用正规模方法求得了扰动电流密度的一般表达式。得到了采用薄电子注时的色散方程。（本刊录）

摘要： 该文提出了同轴波导大回旋半径电子注来用纵向静磁场与径向静电场聚焦，实现回旋潘尼管的设想。用扰动法严格求解了在高频场（TEmn模或TMmn模）作用下，电子的三维运动。详细地分析了回旋同步不稳定性及径向谐振不稳定性、用正规模方法求得了扰动电流密度的一般表达式。得到了采用薄电子注时的色散方程。（本刊录）