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0506nan

木虫 (小有名气)

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专业: 理论和计算化学

[求助] VASP中如何在体系中引入电子和空穴

各位精通VASP的大虾们，我刚看到一篇文献，关于在体系中引入电子和空穴的：
Photoexcitation of electron hole pairs in titania results in charge separation, with electrons available to participate in the CO2 reduction. Here, we assume that the dynamics of charge separation is much faster than electron transfer to CO2; therefore the electrons available for reduction are thermalized to the bottom of TiO2 conduction band (CB), which is about 3.8 eV below the vacuum level.17 Photoexcited electrons are modeled
by introduction of an extra electron into the system, which populates the conduction band of TiO2. The holes which compensate these electrons and interact with them electrostatically are modeled in three possible ways: (i) completely screened and having no inﬂuence (model I); (ii) positive background charge (model II); (iii) localized positive charge in the vicinity,modeled by a proton (model III).

J. Phys. Chem. C 2010, 114, 21474–21481

这三个模型是怎么建的啊？？？VASP中可以同时引入电子和空穴吗？好像MS中不可以啊！没用过VASP，所以不明白这三个模型是怎么建的。

知道的请解释一下，不胜感激！俺比较穷，悬赏10个金币吧^_^

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1楼 2011-06-21 20:22:27

已阅回复此楼关注TA 给TA发消息送TA红花 TA的回帖

0506nan

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引用回帖:

Originally posted by dgcrcat at 2011-06-23 10:56:35:
看了楼主提供的文章的最后一段模型的叙述，加电子，空穴，是分别两个不同的模型，并不是加完电子再加背景电荷吧
但是我也不知道怎么加入，在模型中加入电子或是质子的话，是加在什么位置呢，还是指整个体系的
C ...

作者回复：三种模型的建立。
A positive background charge is added automatically by VASP code if the number of electrons in the system is larger than total charge of atomic cores (see NELECT in the VASP manual) : http://cms.mpi.univie.ac.at/vasp/vasp/Index.html

Model I is a cluster model, and extra electron does not need compensation (complete screening), model III has an extra proton which compensates the negative charge. Please keep in mind that these models are designed to study an extra electron, therefore the goal of introducing hole models is to see how their electrostatic potential influences this extra electron.