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hee_csu

金虫 (著名写手)

[求助] 审稿人对我只用B3LYP有意见

审稿人意见:B3LYP is a functional known to have very large exact exchange component (20%) favoring too loose electron densities and low transition energies. State-of-the-art is to at least use also a functional of the GGA class with zero exact exchange, which will give an impression of the error/spread obtainable from DFT, currently not described.
我的回答:B3LYP, as a hybrid functional parameterized to fit data primarily for main group molecules, has achieved outstanding accuracy and has been widely used in theoretical chemistry calculation. However, B3LYP is known to have very large exact exchange component (20%) favoring too loose electron densities and low transition energies. So, using the pure functional BP86 is necessary, which is a GGA class with zero exact exchange (0%). It can provide another side of the coin. So, we have also performed the geometry optimization, vibrational analysis and excited states calculation using pure functional BP86. The results have been added into the new version of manuscript.

本人纯属量化菜鸟,有个问题,请高手指点:
1、B3LYP中的20%交换相关项是什么?
2、为什么要用纯的泛函BP86来验证?
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lihb734

铁杆木虫 (职业作家)

站在计算化学入门的门槛上

【答案】应助回帖

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zhou2009(金币+3): 2011-10-24 15:47:09
引用回帖:
6楼: Originally posted by lyy880530 at 2011-10-23 11:29:36:
我的审稿意见也是这个意思, it is well known that the B3LYP tends to favor high spin states over low spin states. This is due to the HF exchange energy mixture that has this intrinsic feature and it ...

你早说这个,我就明白了。审稿人的意思,需要你做一个能差与精确交换含量的关系。
你可以测试一下BLYP, B3LYP, BHANDHLYP,看看HF%的影响。期间,你还可调调HF的成分。
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9楼2011-10-24 13:54:23
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lihb734

铁杆木虫 (职业作家)

站在计算化学入门的门槛上

引用回帖:
13楼: Originally posted by yongleli at 2011-10-25 17:16:47:
后边几位量化专家说得很好。
我这里再赠送一个公式:

A*EXSlater+(1-A)*EXHF+B*ΔEXBecke+ECVWN+C*ΔECnon-local

这个式子是说,传统的纯泛函描写电子的行为是过分定域化了。
但是传统的HF计算又过分离域 ...

离域 定域搞反了吧?
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14楼2011-10-25 21:21:37
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