Kinetic Monte Carlo Random Walk Simulation

Description

This code computes a random walk simulation of polaron hopping with kinetic monte carlo sampling as described in this article: (Please cite this article if using this code)

F. Wu, and Y. Ping, Journal of Material Chemistry A 6, 20025-20036 (2018).

Run the program

randomwalk is the main program.

Two files required, $PREFIX.in and $PREFIX.latt.

Run randomwalk $PREFIX to run the program.

calc_activation.py is the script to automate the calculation and post-processing.

• To verify the results, with -n $N option, this program will run the simulation for $N times, and compare results to get error estimation. (Note this is individual to num_trajectory in the input file)

• This script supports parallel runs on a single node with parameter "-np" (suggest np = n)

kairay.sh is an example sbatch script on Kairay to run 3200 and 12800 iterations to show the convergence.

Input file description

*.in : consists of only numbers

num_step_per_sample : run simulation for num_step_per_sample time steps for each L(t)-t data

num_sample : record L(t)-t data in one simulation for num_sample times

num_trajectory : repeat the simulation of num_trajectory times and take the average

number of temperatures

temperature 1

temperature 2

...

Known issues

The time step is estimated from one test run; so if there are sites with very different barriers, the estimated time would be either too much for fast hopping or too less for slow hopping. If the first happens then the program will go out of memory.

Author(s)

Feng Wu

Tyler Smart

Stefano Falletta