!IV.9. Finite difference thermodynamic integration

!This is a example combines an other two free energy simulation
!types. It calculates the Helmholtz free energy
!difference between ethanol and acetone in water, using the finite
!differenece thermdynamic integration. The integrand at
!each quadrature point is obtained by the popular perturbation method.

FILE pm 50
TITL Perturbation method test ethane - acetaldehyde
TITL 3-point Gaussian quadrature (probably inadequate)
HRDW VC32
SVVC SPCC 10.0
SUVC MICC
PBCN FCC    19.57563
TEMP 298 | NSLV 500
STEP    0.10   10.0  0.55      30.0  30
SVPT TIP3 TIP3
SUPT CHRM
!Lambda=0.112702 run
FREE PMLI CCMX
                    0.112702  0.102702  0.122702         0.0     1.0
SLTA SMPL MMC FILE 16 16 8 16 1
CNFG READ ASCI NOFX
!Equilibrate
RUNS 1000000 100000 1000000 1000000 100000
RMCK !Remove equilibration checkpoint file to save disk space
!Production run
RUNS 5000000 100000 1000000 1000000 100000
WCNF ASCI UNCH 60
FILE pm 60
!New coupling parameter - lambda=0.5
FREE PMLI CCMX
                    0.50      0.49      0.51        0.102702 0.122702
!Restore solute to original initial and final state
SLTA SMPL MMC FILE 16 16 8 16 1
!Read starting config from disk to prepare the new
!initial and final states
CNFG READ ASCI NOFX
!Equilibrate
RUNS 1000000 100000 1000000 1000000 100000
RMCK
!Production run
RUNS 5000000 100000 1000000 1000000 100000
WCNF ASCI UNCH 70
!New coupling parameter - lambda=0.887298
FREE PMLI CCMX
                    0.887298  0.877298  0.897298    0.49      0.51
!Restore solute to original initial and final state
SLTA SMPL MMC FILE 16 16 8 16 1
FILE pm 70
CNFG READ ASCI NOFX
!Equilibrate
RUNS 1000000 100000 1000000 1000000 100000
RMCK
!Production run
RUNS 5000000 100000 1000000 1000000 100000
!Evaluate the TI quadrature
TIQU REGL ALL 3 51 10
    0    1    0    0    0
STOP SLFT FULL

!Files needed for run:

!    * pm.50.crd: initial configuration.
!    * pm.slt: description of the two solutes.

!Files created by the run:

!    * pm.crd: initial configuration.
!    * pm.51.ckp, pm.61.ckp, pm.71.ckp: checkpoint files at the quadrature
!      points.
!    * pm.51.crd, pm.52.crd, pm.61.crd, pm.62.crd, pm.71.crd, pm.72.crd:
!      Coordinate files at the end of equilibration and production runs.