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gavinliu7390

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[交流] 【求助】vasp跑分子动力学

有没有用vasp跑分子动力学的。可以分享一下输入文件或经验吗?
Thanks in advance!
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wuchenwf

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gavinliu7390(金币+1):谢谢参与
aylayl08(金币+1,VIP+0):谢谢参与 11-6 09:10
群上有类似讨论,LZ可以找一下
2楼2009-11-05 23:21:43
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wangle_xq

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gavinliu7390(金币+1):谢谢参与
帮顶,最近刚刚开始采用VASP做分子动力学。分子动力学以前也没搞过。所以不清楚要怎么弄。有经验的谈一谈吧。楼上版主说的群,要怎么找?
网络日志 http://blog.163.com/wangle_xq/ 关注计算材料科学的应用,以及相关的计算机技术。文章以转贴为主,少量原创。欢迎参观
3楼2009-11-06 00:58:38
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wangzg9292

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gavinliu7390(金币+1):谢谢参与
他的意思是前面有人讨论过,你搜一下
4楼2009-11-06 13:28:11
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feverforce

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gavinliu7390(金币+1):谢谢参与
aylayl08(金币+2,VIP+0):谢谢提供信息 11-6 14:41
http://cms.mpi.univie.ac.at/vasp/vasp/node233.html
Molecular -- Dynamics

About which files do you have to worry:

param.inc
INCAR
POSCAR
POTCAR
KPOINTS

Use the makeparam utility to create the param.inc file. For a molecular dynamics PREC= Low is definitely sufficient. The INCAR file might be similar to

SYSTEM =  Se
   ENCUT  = 150 eV   ! energy cutoff (opt)
   
   IALGO = 48        ! RMM-DIIS algorithm for electrons
   LREAL  = A        ! evaluate projection operators in real space
   NELMIN = 4        ! do a minimum of four electronic steps
   BMIX   = 2.0      ! mixing parameter
   MAXMIX = 50       ! keep dielectric function between ionic movements

Ionic Relaxation
   ISYM   = 0        ! switch of symmetry
   NSW    =    100   ! number of steps for IOM
   NBLOCK = 1 ; KBLOCK =   100
   SMASS  =    2.0   ! Nose mass-parameter (am)
   POTIM  =   3.00   ! time-step for ion-motion
   TEBEG  =   573    ! temperature

  PC-function
   APACO  = 10.0     ! distance for P.C.

Use IALGO=48 (RMM-DIIS for electrons) for large molecular dynamic runs. You should also evaluate the projection operators in real space (LREAL=A), and require at least 4 electronic iterations per ionic step (NELMIN = 4). For surface you might need to increase this value to NELMIN = 8.

Special consideration require the parameters BMIX and MAXMIX: it is usually desirable to use optimal mixing parameters for molecular dynamics simulations. This can be done by performing a few static calculations with varying AMIX and BMIX parameters and do determine the one leading to the fastest convergence. However in the latest version of VASP the dielectric function is reused when the ions are updated (an optimal AMIX and BMIX is no longer that important). The dielectric function is reused after ionic updates, if MAXMIX ist set. MAXMIX should be about three times as larger as the number of iterations required to converge the electronic wavefunctions in the first iteration.

After doing executing VASP once, it is only necessary to copy CONTCAR to POSCAR and to restart VASP. Usually a shell script is used for this task. An example shell script can be found on the vamp account in the file  vamp/scripts/iter.
5楼2009-11-06 13:29:00
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