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【求助】VASP计算分子在金属表面的吸附出现的问题
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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； |
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2楼2009-05-06 14:41:42
huangyc
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wuchenwf(金币+3,VIP+0):十分感谢！ 5-7 22:40
wuchenwf(金币+3,VIP+0):十分感谢！ 5-7 22:40
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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
4楼2009-05-07 09:37:30
