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adiabatic or diabatic Potential energy surfaces 相关翻译！
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英语太蹩脚，加上专业词汇多，困难太大，请各位高手帮忙！ Potential energy surfaces can be of two types: adiabatic or diabatic. Adiabatic surfaces are defined within the Born–Oppenheimer approximation by the energy (eigenvalue) of a given solution to the electronic Schrodinger equation at each geometry. Such solutions are obtained by using the full electronic Hamiltonian, that is, including kinetic energy, Coulomb, scalar relativistic and spin–orbit terms. Diabatic surfaces can be defined as generated from the eigenvalues of the Schrodinger equation solved using a Hamiltonian from which one or more terms have been omitted; in the present case, the spin–orbit coupling terms. Surfaces of both types are shown for a notional spin-forbidden reaction in Fig. 1. Reactants are on diabatic surface 1 (e.g. corresponding to a triplet state), with products on surface 2 (e.g. a singlet). The corresponding minima have different geometries, and the surfaces cross at the Minimum Energy Crossing Point (MECP). The adiabatic surfaces A and B in Fig. 1 do not cross, as the spin–orbit coupling matrix element H12 = <Ψ1|Hsoc|Ψ2> is non-zero and, therefore, when Hsoc is included in the Hamiltonian, the eigenfunctions are mixtures of different spin states. This means that, in principle, there is a well-defined transition state on the lower surface. In extreme cases, spin–orbit coupling may indeed be so strong that the mixing takes place over a broad range of geometries around the TS, and the reaction can in fact be described in the usual way using standard TST. In practice, for very many cases, the mixing is rather weak and non-adiabatic, non-Born–Oppenheimer behaviour will occur: the system will undergo ‘hops’ from one surface to the other. These can be described either in terms of the diabatic surfaces, as sudden changes in spin state, or in terms of the adiabatic surfaces, as sudden hops from the lower adiabatic surface, A, to the upper one, B. For example, in the limit of very weak spin-orbit coupling, a system approaching the crossing region from the reactant side is most likely, in diabatic terms, to remain on surface 1, and then return to reactants. In adiabatic terms, when the system approaches the very narrowly-avoided crossing between surfaces A and B it will ‘hop’ onto the upper surface. Upon returning from right to left on the diagram, it will hop again at the avoided crossing, back onto surface A and thereby head back to reactants. These two descriptions are equivalent, with the second perhaps more natural to theoretical chemists, but with the first more convenient for our purposes. We will therefore use the diabatic framework throughout. In this terminology, for reaction to occur, spin–orbit coupling must induce a ‘hop’ from surface 1 to surface 2 as the system goes through the crossing region. Hops can occur at any position along the reaction coordinate, but are more likely in the small region around the crossing point where the two surfaces are close in energy. |
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2楼2010-05-05 15:13:00
wanggang126(金币+30, 翻译EPI+1):翻译的挺好，挺专业，大概能明白其中的意思了，太感谢你了！ 2010-05-07 23:28:39
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Potential energy surfaces can be of two types: adiabatic or diabatic. Adiabatic surfaces are defined within the Born–Oppenheimer approximation by the energy (eigenvalue) of a given solution to the electronic Schrodinger equation at each geometry. Such solutions are obtained by using the full electronic Hamiltonian, that is, including kinetic energy, Coulomb, scalar relativistic and spin–orbit terms. Diabatic surfaces can be defined as generated from the eigenvalues of the Schrodinger equation solved using a Hamiltonian from which one or more terms have been omitted; in the present case, the spin–orbit coupling terms. Surfaces of both types are shown for a notional spin-forbidden reaction in Fig. 1. Reactants are on diabatic surface 1 (e.g. corresponding to a triplet state), with products on surface 2 (e.g. a singlet). The corresponding minima have different geometries, and the surfaces cross at the Minimum Energy Crossing Point (MECP). 势能面分为绝热和非绝热两种。绝热势能面是在波恩-奥本海默近似的框架内定义的，指的是在每个几何构型下，电子薛定谔方程的本征值，即能量。上述方程解对应全电子哈密顿算符，即包括电子动能，库仑，标量相对论和旋-轨各项。非绝热势能面可以由使用省略某（些）项的哈密顿的薛定谔方程的本征值解获得；这里省略的是旋-轨项。图一展示自旋禁阻反应模型的两种势能面。反应物在非绝热势能面1上（如，代表一个三重态），产物在势能面2上（如，某个单重态）。相对应的能量最小值处于不同的几何构型，势能面相交于最小能量交叉点（MECP）处。 [ Last edited by c111999 on 2010-5-6 at 00:15 ] |
3楼2010-05-05 23:55:07
wanggang126(金币+30):莫非你是研究这类的？留个QQ以后多多向你请教！ 2010-05-07 23:30:16
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The adiabatic surfaces A and B in Fig. 1 do not cross, as the spin–orbit coupling matrix element H12 = <Ψ1|Hsoc|Ψ2> is non-zero and, therefore, when Hsoc is included in the Hamiltonian, the eigenfunctions are mixtures of different spin states. This means that, in principle, there is a well-defined transition state on the lower surface. In extreme cases, spin–orbit coupling may indeed be so strong that the mixing takes place over a broad range of geometries around the TS, and the reaction can in fact be described in the usual way using standard TST. In practice, for very many cases, the mixing is rather weak and non-adiabatic, non-Born–Oppenheimer behaviour will occur: the system will undergo ‘hops’ from one surface to the other. These can be described either in terms of the diabatic surfaces, as sudden changes in spin state, or in terms of the adiabatic surfaces, as sudden hops from the lower adiabatic surface, A, to the upper one, B. 图一中的绝热势能面A和B不相交，因为旋-轨耦合矩阵元H12= <Ψ1|Hsoc|Ψ2>不为零，因此当旋-轨项Hsoc包括在哈密顿中时，本征函数由不同自旋态混杂而成。这就意味着，理论上，低势能面上有一个定义良好的过渡态。在极端的情况下，旋-轨耦合可能真的强到混杂可以在过渡态附近宽泛的几何构型间发生，反应其实可以用标准的过渡态理论（TST）描述。实际上，在很多情况下，混杂很弱，将会发生非绝热、非波恩-奥本海默行为：系统将从一个势能面“跃迁”至另一个势能面。这种情况可以用非绝热势能面描述，如自旋态突变，或用绝热势能面描述，如突然从低能量的绝热势能面A跃迁至高能绝热势能面B |
4楼2010-05-06 00:14:38
wanggang126(金币+10):本来打算全部给你金币的，但鉴于楼下的朋友也费力不少，希望能理解！还是要感谢你的帮助！ 2010-05-07 23:34:00
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For example, in the limit of very weak spin-orbit coupling, a system approaching the crossing region from the reactant side is most likely, in diabatic terms, to remain on surface 1, and then return to reactants. In adiabatic terms, when the system approaches the very narrowly-avoided crossing between surfaces A and B it will ‘hop’ onto the upper surface. Upon returning from right to left on the diagram, it will hop again at the avoided crossing, back onto surface A and thereby head back to reactants. These two descriptions are equivalent, with the second perhaps more natural to theoretical chemists, but with the first more convenient for our purposes. We will therefore use the diabatic framework throughout. In this terminology, for reaction to occur, spin–orbit coupling must induce a ‘hop’ from surface 1 to surface 2 as the system goes through the crossing region. Hops can occur at any position along the reaction coordinate, but are more likely in the small region around the crossing point where the two surfaces are close in energy. 例如，在极弱旋-轨耦合极限，当系统从反应物一侧接近交叉区域，用非绝热术语表述为系统很有可能继续待在势能面1上，然后返回成反应物。用绝热术语表述为，当系统进入势能面A与B间非常窄的擬交差区域，系统将跃迁至上层势能面。一旦在图中从右向左回到擬交差区域，系统会再次跃迁至势能面A并且在此返回反应物。这两种描述是等价的，第二种对于理论化学工作者更自然，但是第一种更便于达到我们的目的。我们将通篇使用非绝热框架。依此术语，为了让反应进行，在系统通过交叉区域，旋-轨耦合必然引发从势能面1至2的跃迁。跃迁可以在反应坐标上的任意某处发生，然而在两个势能面接近交叉点附近的小范围内更有可能。 [ Last edited by c111999 on 2010-5-6 at 00:37 ] |
5楼2010-05-06 00:31:07
xxsst888
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wanggang126(金币+30):虽然你翻译的不是很如我意，但你也费力不少，故赠30BB,聊表心意，谢谢你的帮助！ 2010-05-07 23:36:11
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溶液中 势能表面的绝热和非绝热现象 溶液的势能表面可分为两种;绝热表面和非绝热表面。可以用几何平面表示。绝热表面特定值能用给定溶液的能量来决定，其值近似于由Schrodinger电子方程算出的 Born-Oppenheimer特征值 。此溶液可按表示电子的Hamiltonian函数获得，其中函数条件要包括动能，库伦电量，标量相对论和自旋轨道理论。而求非绝热表面特定值时可省略一到二个函数条件 。现在的例子忽略自旋轨道耦合项，两种类型的表面显示的是理论上的自旋禁止反应，图 1 。反应物在非绝热表面1（对应于三重态），其产品在表面2（单态），相应的最小值有不同的几何图形，而且，其表面穿过最小能量节点（EMCP） 做为自旋轨道耦合模型，元素H12=《w1 / Hsoc /w2》 不等于零，而且，Hsoc也包含在Hamiltonian函数中。如果这个特征函数是不同自旋状态下的混合的话，那么图1中绝热面A和B不相交。这表明在通常情况下，低的表面有明显的过渡态。在极端情况下，自旋轨道耦合是如此的强以至混合能在试验装置内大范围进行，反应也可以用标准测试来记录。实际上，对大多数实验而言，混合的情况是弱的，散热的，和不符合Born-Oppenheimer现象的。该混合体系经历从一个表面到另一个表面的“跃迁”经历。我们可以用下面两种方式说明绝热和非绝热现象：其一，非绝热表面说明的是自旋状态，或者，绝热表面说明的是跃迁状态。 例如，在非常弱的自旋轨道耦合范围内，混合体系从反应物一方接近节点区时，若以非绝热方法解释，倾向于保持在表面1上，然后再恢复到反应物一方。另一方面，用绝热方法解释，混合体系非常接近表面A和表面B之间的将要接近的区域时，弱自旋轨道耦合将产生跃迁而到上层表面B，图中从右到左所示，为了避免接触形成节点区,自旋轨道耦合将再跃迁一次返回到表面A，也就是向反应物一方跃迁。这两种解释是相等的，第二种解释为理论化学家所倾向，但第一种解释为实验人员所考虑。所以，我们将以非绝热为基础，用这个术语时能说明当反应发生时，形成混合体系将要通过节点区，但自旋轨道的耦合必定诱发从表面1到表面2的跃迁。跃迁可在反应坐标内任何位置发生，但更倾向于在节点附近两个表面能量相似的小区域内发生。 （你有设备做此实验---但愿你有） |
6楼2010-05-06 15:51:10
7楼2010-05-07 23:39:09
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