Tully Model-I (FSSH)

This tutorial demonstrates how to run SHARP Pack for the Tully Model-I in serial mode. Follow the steps below to perform the simulation.

Prepare param.in

First, prepare the input parameter file param.in with the required keywords. For example, at a particular pinit value and nbeads  1 (FSSH method):

#tully model-I input parameters
model        tully1
nParticle    1
nbeads       1
iseed        12345
tstep        1.0
nsteps       3000
ntraj        1000
ncore        1
pinit        20.0
rsamp        gaussian
vsamp        fixed
vreverse     never
rundtail     yes
iprint       10
finish

Run Simulation

Run the simulation using one of the following methods:

1. Direct execution:

   $ ./sharp.x
   

2. Using a job submission script from the utility directory, depending on the computing system:

   # for running on a local machine
   $ sh job-script-local.sh
   
   #for submitting jobs on an HPC cluster (Slurm)
   $ sh job-script-hpc.sh
   

Plot Results with Gnuplot

Plot Energy

• Create a gnuplot script file plot_energy.gnu:

  #!/usr/bin/gnuplot
  set key right top
  
  set term postscript eps colour enhanced 'Helvetica' 24 size 4,4.5
  set border lw 2.5
  set tics scale 2
  
  set output 'fig-energy.pdf'
  NOXTICS = "set xtics (''-10,''-5,''0,''5,''10); \
        unset xlabel"
  XTICS="set xtics -10,5,10;\
     set xlabel '{/Helvetica=22 R (a.u.)}'"
  
  set key  samplen 1.0 spacing 1.3 font "Helvetica, 15"
  set multiplot layout 2,1
  
  @NOXTICS
  set ylabel "{/Helvetica=22 H_{dia} (a.u.)}"
  set yr[-.015:0.02]
  set ytics 0.01
  plot 'energy_surface.out' u 1:2 w l lw 5 t'V_{11}',\
       'energy_surface.out' u 1:5 w l lw 5 t'V_{22}',\
       'energy_surface.out' u 1:3 w l lw 5 dt 3 t'V_{12}'
  
  @XTICS
  set ylabel "{/Helvetica=22 H_{adia} (a.u.)}"
  set yr[-.015:0.02]
  set ytics 0.01
  
  plot 'energy_surface.out' u 1:6 w l lw 5 t'{/Symbol e}_{1}',\
       'energy_surface.out' u 1:7 w l lw 5 t'{/Symbol e}_{2}',\
       'energy_surface.out' u 1:(colum(10)/100) w l lw 5 dt 3 t'd_{12}/100'
  

• Run the gnuplot script to generate the figure as:

  $ gnuplot plot_energy.gnu
  

  

  Fig. 1 Diabatic and adiabatic energy surfaces of Tully1 model.

Plot Populations

• Similarly, create gnuplot script plot_pop.gnu to plot adiabatic or diabatic populations:

#!/usr/bin/gnuplot

set xlabel "Time (a.u.)"
set ylabel "Population"
set title "Tully1 Diabatic Populations"
plot "pop_diabat3.out" u 1:2 w l lw 2 title "Diabatic State 1", \
     "pop_diabat3.out" u 1:3 w l lw 2 title "Diabatic State 2"

Fig. 2 Diabatic population of Tully1 model.