Molecular Conductance from Ab Initio Calculations: Self Energies and Absorbing Boundary Conditions
Molecular Conductance from Ab Initio Calculations: Self Energies and Absorbing Boundary Conditions
复制标题
从头计算的分子电导：自能和吸收边界条件
DOI：
10.1007/978-3-642-14376-2_2
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发表时间：
2006
影响因子：
3.7
通讯作者：
A. Arnold
中科院分区：
文献类型：
--
作者：
F. Evers;A. Arnold
为了理解这个问题的口径，回想一下，描述运输需要跟踪物理现实的两个方面，每一个方面本身都构成了相当困难的任务。需要的是（a）对分子状态有很好的了解，即，能级和轨道，这是不容易获得的，因为它们受到分子上库仑相互作用的强烈影响，和（B）彻底理解这些轨道与电子铅态的杂化，以便预测加宽，即，分子能级的“寿命”。这严重地使从头计算的问题复杂化，因为不可避免地涉及宏观数量的自由度。我们在这里面临着一个经典的困境：这两个问题--分子上的相互作用和铅原子的宏观数量--中的每一个本身都可以得到相当好的处理，但这只能以应用排除另一个问题的同时解决的方法为代价。
In order to appreciate the caliber of the problem, recall that describing transport requires to keep track of two aspects of physical reality, each by itself posing a task of considerable difficulty. Needed are (a) a good knowledge of molecular states, i.e., of energy levels and orbitals, which is not easy to obtain, since they experience a strong influence by Coulomb interactions on the molecule, and (b) a thorough understanding of the hybridization of these orbitals with the electronic lead states, so as to predict the broadening, i.e., the “life time”, of molecular energy levels. This seriously complicates matters for ab initio calculations, because inevitably a macroscopic number of degrees of freedom is involved. We are facing here a classical dilemma: each of the two problems—interactions on the molecule and the macroscopic number of lead atoms—by itself can be dealt with reasonably well, but only at the expense of applying methods that exclude a simultaneous solution of the other problem.