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lgxyz

铜虫 (正式写手)

[求助] 想要得到平滑一些的DOS

各位,想要把dos做的平滑些,我用做金属表面吸附有机分子体系,ISMEAR=-5,NEDOS=1001,出来的峰比较尖,很是难看,请教大家有什么好办法把它搞得平滑些,有人说NEDOS取大些,有人说取小些,还有人说ISMEAR取1或者0,那种方法好一些,请各位赐教!多谢了!
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贺仪

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uuv2010(金币+1): 多谢提示 2011-11-18 23:07:54
引用回帖:
5楼: Originally posted by lgxyz at 2011-11-18 14:45:07:
多谢!取ISMEAR=0会有负占据呀,这个有没有问题,再说mannul上说算dos是要用-5好一些,请你解释下,多谢了!

Mind: Avoid using ISMEAR>0 for semiconductors and insulators, since this often leads to incorrect results (The
occupancies of some states might be larger or smaller than 1). For insulators use ISMEAR=0 or ISMEAR=-5.
The Gaussian smearing (GS) method leads in most cases also to reasonable results. Within this method it is
necessary to extrapolate from finite SIGMA results to SIGMA=0 results. You can find an extra line in the OUTCAR
file ’energy( SIGMA → 0)’ giving the extrapolated results. Large SIGMA values lead to a similar error as the MP
scheme, but in contrast to the MP scheme one can not determine, how large the error due to the smearing is with
systematically reducing SIGMA. Therefore the method of MP is more convenient than the GS method. In addition,
in the GS method forces and the stress tensor are consistent with the free energy and not the energy for SIGMA →
0. Overall the Methfessel-Paxton is easier to use for metallic systems.
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7楼2011-11-18 16:45:38
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likai0106

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lgxyz(金币+5): 2011-11-18 14:29:28
uuv2010(金币+1): 多谢提示 2011-11-18 23:07:26
引用回帖:
1楼: Originally posted by lgxyz at 2011-11-18 12:21:34:
各位,想要把dos做的平滑些,我用做金属表面吸附有机分子体系,ISMEAR=-5,NEDOS=1001,出来的峰比较尖,很是难看,请教大家有什么好办法把它搞得平滑些,有人说NEDOS取大些,有人说取小些,还有人说ISMEAR取1或者 ...

把NEDOS换成500试试看。
2楼2011-11-18 13:51:41
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lgxyz

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2楼: Originally posted by likai0106 at 2011-11-18 13:51:41:
把NEDOS换成500试试看。

多谢!用默认的301也还是尖峰挺多的 要不我把NEDOS降到100试试看,这样应该不会有问题吧
3楼2011-11-18 14:29:10
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贺仪

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lgxyz(金币+5): 2011-11-18 14:45:16
uuv2010(金币+1): 多谢提示 2011-11-18 23:07:34
使用ISMEAR=0,然后调节sigma,sigma越大越平滑,当然你不能随便取,还得按照一定的程序测试一下
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4楼2011-11-18 14:39:39
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