mirror of https://github.com/lammps/lammps.git
232 lines
5.4 KiB
Fortran
232 lines
5.4 KiB
Fortran
! Create LAMMPS data file for 2d LJ simulation of micelles
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!
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! Syntax: micelle2d < def.micelle2d > data.file
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!
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! def file contains size of system and number to turn into surfactants
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! attaches a random surfactant tail(s) to random head
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! if nonflag is set, will attach 2nd-neighbor bonds in surfactant
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! solvent atoms = type 1
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! micelle heads = type 2
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! micelle tails = type 3,4,5,etc.
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MODULE boxmicelle
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IMPLICIT NONE
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PUBLIC
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REAL(KIND=8) :: xprd,yprd,zprd,xboundlo,xboundhi,yboundlo,yboundhi,zboundlo,zboundhi
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CONTAINS
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! periodic boundary conditions - map atom back into periodic box
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SUBROUTINE pbc(x,y)
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REAL(KIND=8), INTENT(inout) :: x,y
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IF (x < xboundlo) x = x + xprd
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IF (x >= xboundhi) x = x - xprd
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IF (y < yboundlo) y = y + yprd
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IF (y >= yboundhi) y = y - yprd
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END SUBROUTINE pbc
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END MODULE boxmicelle
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MODULE rngmicelle
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IMPLICIT NONE
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CONTAINS
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! *very* minimal random number generator
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REAL(KIND=8) FUNCTION random(iseed)
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IMPLICIT NONE
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INTEGER, INTENT(inout) :: iseed
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REAL(KIND=8), PARAMETER :: aa=16807.0_8, mm=2147483647.0_8
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REAL(KIND=8) :: sseed
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sseed = REAL(iseed)
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sseed = MOD(aa*sseed,mm)
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random = sseed/mm
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iseed = INT(sseed)
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END FUNCTION random
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END MODULE rngmicelle
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PROGRAM micelle2d
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USE boxmicelle
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USE rngmicelle
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IMPLICIT NONE
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REAL(kind=8), ALLOCATABLE :: x(:,:)
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INTEGER, ALLOCATABLE :: atomtype(:), molecule(:)
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INTEGER, ALLOCATABLE :: bondatom(:,:),bondtype(:)
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INTEGER :: natoms, maxatom, ntypes, nbonds, nbondtypes, iseed
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INTEGER :: i, j, k, m, nx, ny, nsurf, ntails, nonflag
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REAL(kind=8) :: rhostar, rlattice, sigma, angle,r0
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REAL(kind=8), parameter :: pi = 3.14159265358979323846_8
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LOGICAL :: again
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READ(5,*)
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READ(5,*)
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READ(5,*) rhostar
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READ(5,*) iseed
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READ(5,*) nx,ny
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READ(5,*) nsurf
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READ(5,*) r0
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READ(5,*) ntails
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READ(5,*) nonflag
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natoms = nx*ny
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maxatom = natoms + nsurf*ntails
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ALLOCATE(x(2,maxatom), molecule(maxatom), atomtype(maxatom))
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nbonds = nsurf*ntails
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IF (nonflag.EQ.1) nbonds = nbonds + nsurf*(ntails-1)
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ALLOCATE(bondatom(2,nbonds), bondtype(nbonds))
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! box size
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rlattice = (1.0_8/rhostar) ** 0.5_8
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xboundlo = 0.0_8
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xboundhi = nx*rlattice
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yboundlo = 0.0_8
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yboundhi = ny*rlattice
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zboundlo = -0.1_8
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zboundhi = 0.1_8
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sigma = 1.0_8
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xprd = xboundhi - xboundlo
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yprd = yboundhi - yboundlo
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zprd = zboundhi - zboundlo
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! initial square lattice of solvents
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m = 0
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DO j = 1,ny
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DO i = 1,nx
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m = m + 1
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x(1,m) = xboundlo + (i-1)*rlattice
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x(2,m) = yboundlo + (j-1)*rlattice
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molecule(m) = 0
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atomtype(m) = 1
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ENDDO
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ENDDO
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! turn some into surfactants with molecule ID
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! head changes to type 2
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! create ntails for each head of types 3,4,...
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! each tail is at distance r0 away in straight line with random orientation
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DO i = 1,nsurf
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again = .TRUE.
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DO WHILE(again)
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m = INT(random(iseed)*natoms + 1)
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IF (m > natoms) m = natoms
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IF (molecule(m) /= 0) CYCLE
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again = .FALSE.
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END DO
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molecule(m) = i
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atomtype(m) = 2
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angle = random(iseed)*2.0_8*pi
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DO j = 1,ntails
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k = (i-1)*ntails + j
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x(1,natoms+k) = x(1,m) + COS(angle)*j*r0*sigma
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x(2,natoms+k) = x(2,m) + SIN(angle)*j*r0*sigma
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molecule(natoms+k) = i
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atomtype(natoms+k) = 2+j
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CALL pbc(x(1,natoms+k),x(2,natoms+k))
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IF (j == 1) bondatom(1,k) = m
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IF (j /= 1) bondatom(1,k) = natoms+k-1
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bondatom(2,k) = natoms+k
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bondtype(k) = 1
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ENDDO
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ENDDO
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! if nonflag is set, add (ntails-1) 2nd nearest neighbor bonds to end
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! of bond list
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! k = location in bondatom list where nearest neighbor bonds for
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! this surfactant are stored
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IF (nonflag == 1) THEN
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nbonds = nsurf*ntails
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DO i = 1,nsurf
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DO j = 1,ntails-1
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k = (i-1)*ntails + j
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nbonds = nbonds + 1
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bondatom(1,nbonds) = bondatom(1,k)
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bondatom(2,nbonds) = bondatom(2,k+1)
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bondtype(nbonds) = 2
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ENDDO
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ENDDO
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ENDIF
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! write LAMMPS data file
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natoms = natoms + nsurf*ntails
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nbonds = nsurf*ntails
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IF (nonflag == 1) nbonds = nbonds + nsurf*(ntails-1)
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ntypes = 2 + ntails
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nbondtypes = 1
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IF (nonflag == 1) nbondtypes = 2
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IF (nsurf == 0) THEN
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ntypes = 1
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nbondtypes = 0
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ENDIF
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WRITE (6,*) 'LAMMPS 2d micelle data file'
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WRITE (6,*)
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WRITE (6,*) natoms,' atoms'
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WRITE (6,*) nbonds,' bonds'
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WRITE (6,*) 0,' angles'
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WRITE (6,*) 0,' dihedrals'
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WRITE (6,*) 0,' impropers'
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WRITE (6,*)
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WRITE (6,*) ntypes,' atom types'
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WRITE (6,*) nbondtypes,' bond types'
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WRITE (6,*) 0,' angle types'
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WRITE (6,*) 0,' dihedral types'
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WRITE (6,*) 0,' improper types'
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WRITE (6,*)
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WRITE (6,*) xboundlo,xboundhi,' xlo xhi'
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WRITE (6,*) yboundlo,yboundhi,' ylo yhi'
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WRITE (6,*) zboundlo,zboundhi,' zlo zhi'
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WRITE (6,*)
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WRITE (6,*) 'Masses'
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WRITE (6,*)
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DO i = 1,ntypes
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WRITE (6,*) i,1.0
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ENDDO
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WRITE (6,*)
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WRITE (6,*) 'Atoms # molecular'
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WRITE (6,*)
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DO i = 1,natoms
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WRITE (6,'(3I7,3F8.3)') i,molecule(i),atomtype(i),x(1,i),x(2,i),0.0
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ENDDO
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IF (nsurf > 0) THEN
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WRITE (6,*)
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WRITE (6,*) 'Bonds'
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WRITE (6,*)
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DO i = 1,nbonds
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WRITE (6,'(4I7)') i,bondtype(i),bondatom(1,i),bondatom(2,i)
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ENDDO
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ENDIF
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DEALLOCATE(x,molecule,atomtype,bondtype,bondatom)
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END PROGRAM micelle2d
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