[ defaults ]
; nbfunc   comb-rule   gen-pairs  fudgeLJ  fudgeQQ
     1       3          no       1.0     0.0
 
 [ atomtypes ]
; name   mass   charge   ptype   c6   c12
  C1     12.01100    0.0   A     0.35000     0.27612
  C2     12.01100    0.0   A     0.35000     0.27612
  H1      1.00790    0.0   A     0.25000     0.12555
  H2      1.00790    0.0   A     0.25000     0.12555


 [ moleculetype ]
; Name     nrexcl
  but         3
 
 [ atoms ]
;   nr   type  resnr residue  atom  cgnr charge  mass
    1 C1             1 but        C1             1     0.0000      12.0110
    2 C2             1 but        C2             2     0.0000      12.0110
    3 C2             1 but        C2             3     0.0000      12.0110
    4 C1             1 but        C1             4     0.0000      12.0110
    5 H1             1 but        H1             5     0.0000       1.0079
    6 H1             1 but        H1             6     0.0000       1.0079
    7 H1             1 but        H1             7     0.0000       1.0079
    8 H2             1 but        H2             8     0.0000       1.0079
    9 H2             1 but        H2             9     0.0000       1.0079
   10 H2             1 but        H2            10     0.0000       1.0079
   11 H2             1 but        H2            11     0.0000       1.0079
   12 H1             1 but        H1            12     0.0000       1.0079
   13 H1             1 but        H1            13     0.0000       1.0079
   14 H1             1 but        H1            14     0.0000       1.0079
 
[ bonds ]
;  ai    aj   type    r0          kr

 [ angles ]
; ai    aj   ak   type     theta0           kt

 [ dihedrals ]
;  ai    aj    ak    al   type     gamma        kd

 
 [ system ]
; Name
 Butane 
 
 [ molecules ]
; Compound        #mols
but                1