[gmx-users] breaking down total energy

Moeed lecielll at googlemail.com
Thu May 20 04:35:17 CEST 2010


Hello Justin,

Thanks for your comments. Actually, since I am interested in only
interaction energies *between* molecules I thought by excluding energies
between atoms on a single chain what I get from nonbonded interactions would
not include 1-4 interactions.

*********************************************
This is from previous posts:

Question: Can I not take for
instance LJ energy values which are coming from a specific NO. of molecuels
in simulation box and calculate interaction energies for pairs or "mol"
number of molecules?

Your answer:

Not easily.  You will still have intramolecular terms that are not covered
by
the 1-4 interactions.  *For example, if the two ends of your molecule
interact
with one another, this interaction will contribute to your nonbonded
energies.*
*********************************************************************************************
That is why I thought I have to exclude interaction in a single chain
between atoms, so that for instance atoms 1 and 20 do not see each other.

I manual I found only about how extra exlusion within a molecue cab added in
[exclusions].. I dont think this helps me.

How can I define all possible intramolecular exclusions in order to save
only intermolecular energy contributions?


top file:

Include forcefield parameters

#include "ffoplsaa.itp"

[ moleculetype ]
; Name            nrexcl
Hexane              3

[ exclusions ]
??

[ 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_140      1    HEX    H11      1       0.06      1.008
; qtot -0.12
     3   opls_140      1    HEX    H12      1       0.06      1.008
; qtot -0.06
     4   opls_140      1    HEX    H13      1       0.06      1.008   ; qtot 0
     5   opls_158      1    HEX     C2      2      -0.12     12.011
; qtot -0.12
     6   opls_140      1    HEX    H21      2       0.06      1.008
; qtot -0.06
     7   opls_140      1    HEX    H22      2       0.06      1.008   ; qtot 0
     8   opls_158      1    HEX     C3      3      -0.12     12.011
; qtot -0.12
     9   opls_140      1    HEX    H31      3       0.06      1.008
; qtot -0.06
    10   opls_140      1    HEX    H32      3       0.06      1.008   ; qtot 0
    11   opls_158      1    HEX     C4      4      -0.12     12.011
; qtot -0.12
    12   opls_140      1    HEX    H41      4       0.06      1.008
; qtot -0.06
    13   opls_140      1    HEX    H42      4       0.06      1.008   ; qtot 0
    14   opls_158      1    HEX     C5      5      -0.12     12.011
; qtot -0.12
    15   opls_140      1    HEX    H51      5       0.06      1.008
; qtot -0.06
    16   opls_140      1    HEX    H52      5       0.06      1.008   ; qtot 0
    17   opls_157      1    HEX     C6      6      -0.18     12.011
; qtot -0.18
    18   opls_140      1    HEX    H61      6       0.06      1.008
; qtot -0.12
    19   opls_140      1    HEX    H62      6       0.06      1.008
; qtot -0.06
    20   opls_140      1    HEX    H63      6       0.06      1.008   ; qtot 0

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

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

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

[ dihedrals ]
;  ai    aj    ak    al funct            c0            c1
c2            c3            c4            c5
    2     1     5     6     3
    2     1     5     7     3
    2     1     5     8     3
    3     1     5     6     3
    3     1     5     7     3
    3     1     5     8     3
    4     1     5     6     3
    4     1     5     7     3
    4     1     5     8     3
    1     5     8     9     3
    1     5     8    10     3
    1     5     8    11     3
    6     5     8     9     3
    6     5     8    10     3
    6     5     8    11     3
    7     5     8     9     3
    7     5     8    10     3
    7     5     8    11     3
    5     8    11    12     3
    5     8    11    13     3
    5     8    11    14     3
    9     8    11    12     3
    9     8    11    13     3
    9     8    11    14     3
   10     8    11    12     3
   10     8    11    13     3
   10     8    11    14     3
    8    11    14    15     3
    8    11    14    16     3
    8    11    14    17     3
   12    11    14    15     3
   12    11    14    16     3
   12    11    14    17     3
   13    11    14    15     3
   13    11    14    16     3
   13    11    14    17     3
   11    14    17    18     3
   11    14    17    19     3
   11    14    17    20     3
   15    14    17    18     3
   15    14    17    19     3
   15    14    17    20     3
   16    14    17    18     3
   16    14    17    19     3
   16    14    17    20     3

; Include Position restraint file
;#ifdef POSRES
;#include "posre.itp"
;#endif

; Include water topology
;#include "spc.itp"

;#ifdef POSRES_WATER
; Position restraint for each water oxygen
;[ position_restraints ]
;  i funct       fcx        fcy        fcz
 ;  1    1       1000       1000       1000
;#endif

; Include generic topology for ions
;#include "ions.itp"

[ system ]
; Name
Hexane

[ molecules ]
; Compound        #mols
Hexane              125



Thank you,
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