[gmx-users] Neighbor search and rlist

[Janne Hirvi]

Hello!

There has been lots of conversation about rlist and cut-off parameters in the
mailing list, but however I still have some questions.

1) I thought, that rlist should always be a little bit larger than rvdw, but the
manual states that it isn't the case with single range cut-off and grompp
agrees with that with a comment: with vdwtype=cut-off, rvdw must be >=rlist
(version 3.3). Is this (rlist=rvdw) a huge problem when I use charge-groups or
is there some invisible parameter (X), which increases neighbor search cut-off
(rlist+X)?

2) How about then rlist vs. rcoulomb, when I use PME. Do I need to have
rlist>rcoulomb or rlist=rcoulomb as the manual suggests? Actually the suggested
parameters of the manual are rlist=rcoulomb=rvdw.


Crusial parameters:

nstlist             =  10
rlist               =  1.2 (1.5???) 
coulombtype         =  PME
rcoulomb            =  1.2
vdwtype             =  Cut-off or User(table 0-4.0nm)
rvdw                =  1.2
 

Thanks for any help or comments! 
 
Janne
 
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Janne Hirvi, MSc(Physical Chemistry), Researcher
University of Joensuu, Department of Chemistry, P.O.Box 111 80101 Joensuu, FI
Tel: +358 13 2514544 & +358 50 3474223
E-mail: Janne.Hirvi at joensuu.fi & hirvi at cc.joensuu.fi
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