24小时热门版块排行榜    

查看: 525  |  回复: 3
当前主题已经存档。

longchang

金虫 (小有名气)

[交流] 【求助】VASP计算分子在金属表面的吸附出现的问题

我现在试用VASP计算分子在金属表面的吸附,但计算过程中总会显示“ZBRENT:can't locate minium,use default step";也会出现”ZBRENT:increasing interval",虽然结果能算出来,但到底问题出现在那里?
  general:
   SYSTEM =
   ISTART = 0
   ICHARG = 2
   ENCUT=400
   GGA=91
   VOSKOWN=1
   NELM=200
   ISMEAR = 2  
   SIGMA = 0.2
   ALGO=F
   PREC=N
   NGX =26
   NGY =26
   NGZ =70
dynamic:
   NSW=200
   POTIM = 0.2
   IBRION =2

k-points用的是5X5X1;
回复此楼
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

longchang

金虫 (小有名气)

后来将k-points改为9X9X1,增大POTIM也不行,哪位高手帮帮忙?
2楼2009-05-06 14:41:42
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

huangyc

木虫 (正式写手)

★ ★ ★
wuchenwf(金币+3,VIP+0):十分感谢! 5-7 22:40
参照 http://cms.mpi.univie.ac.at/vasp-forum/forum_viewtopic.php?3.1856

ZBRENT is an algorithm search for a root of a function by Brent's method: Numerical recipies, Section 9.3
The problem in your case might be that the Conjugate Gradient algorithm (IBRION=2) is not suitable for very small corrections of the atomic positions if your system has almost reached equilibrium (please have a look at XDATCAR to check the size of the relaxation steps done before the ZBRENT warnings show up). Usually it is sufficient to converge a system up to maximum remaining forces of about 0.01eV/A (EDIFFG=-0.01).
please try one of the following:
1) choose a different algorithm for ionic optimization (IBRION=1)
2) set ADDGRID=.True. in INCAR (only for vasp releases 4.4.5 and newer)
3楼2009-05-06 23:04:56
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

longchang

金虫 (小有名气)

十分感谢!
4楼2009-05-07 09:37:30
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
相关版块跳转 我要订阅楼主 longchang 的主题更新
普通表情 高级回复 (可上传附件)
信息提示
请填处理意见