[gmx-users] grompp error, invalid line in .gro file

[Andreas Kring]

Hello all.

I'm trying to simulate an argon liquid. The OPLS-AA force field is used 
with the files from /usr/local/gromacs/share/gromacs/top. But I get an 
error when I run

$ grompp -f NVT.mdp -c Ar.gro -p Ar.top
-------------------------------------------------------
Program grompp, VERSION 3.3.3
Source code file: confio.c, line: 709

Fatal error:
Invalid line in Ar.gro for atom 1:
1Argon Ar 1 0.0 0.0 0.0
-------------------------------------------------------

An ideas on what can be wrong? My argon .top file and .gro file can be 
seen below.

Kind regards
Andreas

----------------------
Ar.top
----------------------
; Topology file for Ar

; Parameter level

#include "ffoplsaa.itp"
;            #define _FF_OPLS
;            #define _FF_OPLSAA
;            [defaults]
;            #include "ffoplsaanb.itp"
;               [atomtypes]
;            #include "ffoplsaabon.itp"
;               [bondtypes]
;               [constrainttypes]
;               [angletypes]
;               [dihedraltypes]

; Molecule level

[ moleculetype ]
; molname	nrexcl
Argon		1

[ atoms ]
; id	at_type	res_nr	res_name	at_name	cg_nr	charge
1	opls_097	1	Argon	Ar	1	0.0

; System level

[ system ]
Argon liquid

[ molecules ]
Argon 2048

---------------------------------
Ar.gro
---------------------------------
fcc lattice of argon atoms
2048
1Argon Ar 1 0.0 0.0 0.0
2Argon Ar 2 0.283835 0.283835 0.0
...
2047Argon Ar 2047 4.257525 3.97369 4.257525
2048Argon Ar 2048 3.97369 4.257525 4.257525
4.54136 4.54136 4.54136