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2008210014

[交流] 【求助】LDA+ U,U的设置

用CASTEP计算V掺杂ZnO,想加U计算,那么除了ZN 加U, V也要加的对吗,在文献中ZN 的倒是很多,很少看见V的U取值,如果自己测试U值的话,根据什么判断哪个U更合适呢,谢谢
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fuzp

铁杆木虫 (正式写手)

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spur(金币+2,VIP+0):欢迎讨论! 5-23 08:52
2008210014(金币+1,VIP+0):Zn的一般都有加U算的,是根据实验值也对比的,哪个跟实验值更接近,就采用哪个,但是像V的还没见过 5-23 09:59
2008210014(金币+1,VIP+0):谢谢 10-30 10:54
V是要加U的,但是设成多少应该根据你要算的物性来看,感觉没有什么严格的标准。

Help里是这样描述的:
Default effective Hubbard U values should be considered as guidelines only, as they are not universal and depend greatly on the chemical environment. The results obtained depend on the value of U as well as the atomic orbitals, so literature values are often inappropriate.
This parameter can be calculated theoretically. However, experience shows that the best results are achieved when the U parameter is allowed to vary depending on the property of interest. CASTEP therefore does not calculate the value of U but uses it as an input parameter.

[ Last edited by fuzp on 2009-5-23 at 05:48 ]
3楼2009-05-23 05:40:55
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