[gmx-users] How to reduce high repulsion from system?

Moeed lecielll at googlemail.com
Thu Apr 29 22:02:24 CEST 2010


Dear experts,

Could you please take a look at energy values. The system contains only
stack of hexane molecules. MD sun gives lincs warning.

1- How can I get rid of high repulsive potential?

*genconf_d -f Hexane.gro -nbox 4.0 8.0 8.0 -dist 1.1 0.55 0.55 -o
Hexane-stack.gro*


********------------------------***************************************************************************
energy minimization
my output.mdrun_em:

Steepest Descents converged to Fmax < 1000 in 30 steps
Potential Energy  =  4.76092783832156e+05
Maximum force     =  9.86600079729483e+02 on atom 3115
Norm of force     =  5.33725886931530e+02
*********************************************************************************************************
g_energy file:

Statistics over 61 steps [ 0.0000 thru 0.1200 ps ], 12 data sets
All averages are exact over 61 steps

Energy                      Average       RMSD     Fluct.      Drift
Tot-Drift
------------------------------
-------------------------------------------------
Angle                       78416.5    38731.2    25083.3     838187
102231
LJ-14                    1.16009e+08 8.87401e+08 8.87401e+08 3.06025e+06
373250
Coulomb-14                  734.065    480.683    140.481    13056.3
1592.44
LJ (SR)                     5482.29    5991.07    4445.16     114080
13914.1
Coulomb (SR)                1711.47    732.288    228.708     -19758
-2409.83
Potential                1.16326e+08 8.8739e+08 8.8739e+08     921124
112347
Kinetic En.              1.77327e+18 5.4851e+18 4.28286e+18 9.73294e+19
1.1871e+19
Total Energy             1.77327e+18 5.4851e+18 4.28286e+18 9.73294e+19
1.1871e+19
Temperature              4.06507e+16 1.25741e+17 9.81811e+16 2.2312e+18
2.72133e+17
Pressure (bar)           1.48406e+15 4.59052e+15 3.58436e+15 8.14557e+16
9.93493e+15
T-HEX                    4.06507e+16 1.25741e+17 9.81811e+16 2.2312e+18
2.72133e+17
Lamb-HEX                    0.99144 0.00206848          0 -0.0617392
-0.00753016
Heat Capacity Cv:    -0.934076 J/mol K (factor = 9.56799)

***************
*************************************************************************

title               = Hexane
cpp                 = /lib/cpp

;        Run control
integrator          =  md
dt                  =  0.002        ; ps !
nsteps              =  5000        ; total 1.0 ps.
nstcomm             =  1        ; frequency for center of mass motion
removal

;        Output control
nstenergy           =  10        ; frequency to write energies to energy
file. i.e., energies and other statistical data are stored every 10 steps
nstxout             =  10        ; frequency to write
coordinates/velocity/force to output trajectory file
nstvout             =  0
nstfout             =  10
nstlog              =  10        ; frequency to write energies to log file

;        Neighbor searching
nstlist             =  10        ; neighborlist will be updated at least
every 10 steps
;ns_type             =  grid

;        Electrostatics/VdW
coulombtype         =  cut-off
vdw-type            =  cut-off
;        Cut-offs
rlist               =  1.0
rcoulomb            =  1.0
rvdw                =  1.0

;        Temperature coupling    Berendsen temperature coupling is on in two
groups
Tcoupl              =  berendsen
tc-grps             =  HEX      ;sol
tau_t               =  0.1      ;0.1
ref_t               =  300      ;300

;        Pressure coupling:     Pressure coupling is not on
Pcoupl              =  no
tau_p               =  0.5
compressibility     =  4.5e-5
ref_p               =  1.0

;        Velocity generation    Generate velocites is on at 300 K. Manual
p155
gen_vel             =  yes
gen_temp            =  300.0
gen_seed            =  173529

;        Bonds
constraints         =  all-bonds
constraint-algorithm = lincs

pbc=xyz

****************************************************************************************
;
;    File 'Hexane.top' was generated
;    By user: moeed (500)
;    On host: moeed-desktop
;    At date: Thu Apr  8 13:51:19 2010
;
;    This is your include topology file
;    Generated by x2top
;
; Include forcefield parameters
#include "ffoplsaa.itp"

[ moleculetype ]
; Name            nrexcl
HEX                 3

[ atoms ]
;   nr       type  resnr residue  atom   cgnr     charge       mass
typeB    chargeB      massB
     1   opls_157      1   HEX      C1      1      -0.18     12.011   ; qtot
-0.18
     2   opls_158      1   HEX      C2      2      -0.12     12.011   ; qtot
-0.3
     3   opls_158      1   HEX      C3      3      -0.12     12.011   ; qtot
-0.42
     4   opls_158      1   HEX      C4      4      -0.12     12.011   ; qtot
-0.54
     5   opls_158      1   HEX      C5      5      -0.12     12.011   ; qtot
-0.66
     6   opls_157      1   HEX      C6      6      -0.18     12.011   ; qtot
-0.84
     7   opls_140      1   HEX      H1      6       0.06      1.008   ; qtot
-0.78
     8   opls_140      1   HEX      H2      6       0.06      1.008   ; qtot
-0.72
     9   opls_140      1   HEX      H3      6       0.06      1.008   ; qtot
-0.66
    10   opls_140      1   HEX      H4      5       0.06      1.008   ; qtot
-0.6
    11   opls_140      1   HEX      H5      5       0.06      1.008   ; qtot
-0.54
    12   opls_140      1   HEX      H6      4       0.06      1.008   ; qtot
-0.48
    13   opls_140      1   HEX      H7      4       0.06      1.008   ; qtot
-0.42
    14   opls_140      1   HEX      H8      3       0.06      1.008   ; qtot
-0.36
    15   opls_140      1   HEX      H9      3       0.06      1.008   ; qtot
-0.3
    16   opls_140      1   HEX     H10      2       0.06      1.008   ; qtot
-0.24
    17   opls_140      1   HEX     H11      2       0.06      1.008   ; qtot
-0.18
    18   opls_140      1   HEX     H12      1       0.06      1.008   ; qtot
-0.12
    19   opls_140      1   HEX     H13      1       0.06      1.008   ; qtot
-0.06
    20   opls_140      1   HEX     H14      1       0.06      1.008   ; qtot
0

[ bonds ]
;  ai    aj funct            c0            c1            c2            c3
    1     2     1  1.530000e-01  4.000000e+05  1.530000e-01  4.000000e+05
    1    18     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    1    19     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    1    20     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    2     3     1  1.530000e-01  4.000000e+05  1.530000e-01  4.000000e+05
    2    16     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    2    17     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    3     4     1  1.540000e-01  4.000000e+05  1.540000e-01  4.000000e+05
    3    14     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    3    15     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    4     5     1  1.530000e-01  4.000000e+05  1.530000e-01  4.000000e+05
    4    12     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    4    13     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    5     6     1  1.530000e-01  4.000000e+05  1.530000e-01  4.000000e+05
    5    10     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    5    11     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    6     7     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    6     8     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05
    6     9     1  1.090000e-01  4.000000e+05  1.090000e-01  4.000000e+05

[ pairs ]
;  ai    aj funct            c0            c1            c2            c3
    1     4     1
    1    14     1
    1    15     1
    2     5     1
    2    12     1
    2    13     1
    3     6     1
    3    10     1
    3    11     1
    3    18     1
    3    19     1
    3    20     1
    4     7     1
    4     8     1
    4     9     1
    4    16     1
    4    17     1
    5    14     1
    5    15     1
    6    12     1
    6    13     1
    7    10     1
    7    11     1
    8    10     1
    8    11     1
    9    10     1
    9    11     1
   10    12     1
   10    13     1
   11    12     1
   11    13     1
   12    14     1
   12    15     1
   13    14     1
   13    15     1
   14    16     1
   14    17     1
   15    16     1
   15    17     1
   16    18     1
   16    19     1
   16    20     1
   17    18     1
   17    19     1
   17    20     1

[ angles ]
;  ai    aj    ak funct            c0            c1            c2
c3
    2     1    18     1  1.120000e+02  4.000000e+02  1.120000e+02
4.000000e+02
    2     1    19     1  1.110000e+02  4.000000e+02  1.110000e+02
4.000000e+02
    2     1    20     1  1.110000e+02  4.000000e+02  1.110000e+02
4.000000e+02
   18     1    19     1  1.070000e+02  4.000000e+02  1.070000e+02
4.000000e+02
   18     1    20     1  1.070000e+02  4.000000e+02  1.070000e+02
4.000000e+02
   19     1    20     1  1.080000e+02  4.000000e+02  1.080000e+02
4.000000e+02
    1     2     3     1  1.130000e+02  4.000000e+02  1.130000e+02
4.000000e+02
    1     2    16     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
    1     2    17     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
    3     2    16     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
    3     2    17     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
   16     2    17     1  1.060000e+02  4.000000e+02  1.060000e+02
4.000000e+02
    2     3     4     1  1.130000e+02  4.000000e+02  1.130000e+02
4.000000e+02
    2     3    14     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
    2     3    15     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
    4     3    14     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
    4     3    15     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
   14     3    15     1  1.060000e+02  4.000000e+02  1.060000e+02
4.000000e+02
    3     4     5     1  1.130000e+02  4.000000e+02  1.130000e+02
4.000000e+02
    3     4    12     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
    3     4    13     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
    5     4    12     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
    5     4    13     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
   12     4    13     1  1.060000e+02  4.000000e+02  1.060000e+02
4.000000e+02
    4     5     6     1  1.130000e+02  4.000000e+02  1.130000e+02
4.000000e+02
    4     5    10     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
    4     5    11     1  1.100000e+02  4.000000e+02  1.100000e+02
4.000000e+02
    6     5    10     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
    6     5    11     1  1.090000e+02  4.000000e+02  1.090000e+02
4.000000e+02
   10     5    11     1  1.060000e+02  4.000000e+02  1.060000e+02
4.000000e+02
    5     6     7     1  1.110000e+02  4.000000e+02  1.110000e+02
4.000000e+02
    5     6     8     1  1.110000e+02  4.000000e+02  1.110000e+02
4.000000e+02
    5     6     9     1  1.120000e+02  4.000000e+02  1.120000e+02
4.000000e+02
    7     6     8     1  1.080000e+02  4.000000e+02  1.080000e+02
4.000000e+02
    7     6     9     1  1.070000e+02  4.000000e+02  1.070000e+02
4.000000e+02
    8     6     9     1  1.070000e+02  4.000000e+02  1.070000e+02
4.000000e+02

[ dihedrals ]
;  ai    aj    ak    al funct            c0            c1
c2            c3            c4            c5
   18     1     2     3     3  3.600000e+02  5.000000e+00  3.000000e+00
3.600000e+02  5.000000e+00  3.000000e+00
    1     2     3     4     3  3.600000e+02  5.000000e+00  3.000000e+00
3.600000e+02  5.000000e+00  3.000000e+00
    2     3     4     5     3  3.600000e+02  5.000000e+00  3.000000e+00
3.600000e+02  5.000000e+00  3.000000e+00
    3     4     5     6     3  3.600000e+02  5.000000e+00  3.000000e+00
3.600000e+02  5.000000e+00  3.000000e+00
    4     5     6     7     3  3.600000e+02  5.000000e+00  3.000000e+00
3.600000e+02  5.000000e+00  3.000000e+00

[ system ]
; Name
HEX

[ molecules ]
; Compound        #mols
HEX                 256
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