#!/bin/sh

# == IRC scan of the reaction path ==


# The IRC calculation is split in two steps to illustrate the Restart feature.

# In the first calculation only a few points are computed along the so-called 
# 'forward' path. The definition of which is 'forward' and which is
# 'backward' depends on the sign of the largest component of the normal mode
# corresponding to the reaction coordinate. 

# The RKF file from this partial IRC scan serves as restart file
# for the next calculations that will continue the IRC scan.

# The 'MaxPoints' key in the IRC block is used to limit the number of IRC 
# points to compute.


AMS_JOBNAME=irc1 $AMSBIN/ams << eor

Task IRC
System
    Atoms
        C       0.000000000000       0.000000000000       0.000000000000    
        N       0.000000000000       0.000000000000      -1.182644220000    
        H      -1.103250760411       0.000000000000      -0.322462130000    
    End
End

IRC
    MaxPoints 5
    Direction Forward
    CoordinateType Cartesian
    InitialHessian
        Type Calculate
    End
End

Engine DFTB
    Model DFTB3
    ResourcesDir DFTB.org/3ob-3-1
EndEngine

eor

# In the second IRC run, the IRC scan is finished. We start with the RKF file
# from the previous run and omit the MaxPoints from the settings, which means 
# that the default 100 will be used. Note that the 100 also includes any points 
# computed in the previous calculation. The program starts on
# the forward path, continuing where the first calculation had stopped,
# and completes it. Since we set the Direction to Both
# then AMS proceeds to the backward path. After both paths are finished a summary 
# of the path characteristics is printed at the end of the output file.


AMS_JOBNAME=irc2 $AMSBIN/ams << eor

Task IRC
System
    Atoms
        C       0.000000000000       0.000000000000       0.000000000000    
        N       0.000000000000       0.000000000000      -1.182644220000    
        H      -1.103250760411       0.000000000000      -0.322462130000    
    End
End

IRC
    Restart
        File irc1.results/ams.rkf
    End
    ! Change options from the ones found in the restart file 
    ! (MaxIRCPoints and MaxPoints will be reset to defaults automatically)
    Direction Both
End

Engine DFTB
    Model DFTB3
    ResourcesDir DFTB.org/3ob-3-1
EndEngine

eor