# Problem in calculating kappa value

Dear lammps user,
I am a beginner of lammps. I am trying to calculate thermal conductivity of graphene nanoribbon using muller-plathe algorithm.For this i equlibriate the system then run for thermal conductivity using the following input

.#Thermal Conductivity of Graphene
pair_style tersoff
pair_coeff * * SiC.tersoff C C

log log.thermal
variable t equal 15000
thermo \$t
fix 1 all nvt temp 300.0 300.0 1.0
compute ke all ke/atom
variable temperature atom c_ke/(1.5*8.617e-5)
fix 2 all ave/spatial 1 100 100 x lower 2.46 v_temperature file temp.graphenedoped50 units box
fix 3 all thermal/conductivity 300 x 46
variable tdiff equal f_2[45][3]-f_2[1][3]
thermo_style custom step temp pe ke etotal press lx ly lz f_3 v_tdiff
run 100000
write_restart equil.restart4
fix 2 all ave/spatial 1 100 100 x lower 2.46 v_temperature file temp.graphenedoped50 units box
run 100000
write_restart equil.restart5
fix 3 all thermal/conductivity 300 x 46
fix ave all ave/time 1 1 1000 v_tdiff ave running
thermo_style custom step temp epair etotal f_3 v_tdiff f_ave

run 100000

But i am facing problem in extracting kappa value from the log file…Here for detailed information i have attached input and log file
Could anyone please guide me to calculate kappa value. Thanking you in advance. I am waiting for any kind suggestion.
Sincerely,
Pooja Kansa Banik
Project student
Department of physics, Assam University

input.txt.txt (897 Bytes)

log.thermal (8.1 KB)

Dear lammps user,
I am a beginner of lammps. I am trying to calculate thermal conductivity of graphene nanoribbon using muller-plathe algorithm.For this i equlibriate the system then run for thermal conductivity using the following input

[…]

But i am facing problem in extracting kappa value from the log file…Here for detailed information i have attached input and log file
Could anyone please guide me to calculate kappa value. Thanking you in advance. I am waiting for any kind suggestion.

please use the information from the LAMMPS manual (there is a howto on thermal conductivity, the documentation for fix thermal/conductivity, and the information in the README file of the examples/KAPPA folder).

there should also be discussions on the various approaches in the mailing list archive.

axel.

This talk is also very descriptive. It walks through the Muller-Plathe methodology, how to implement it in LAMMPS, and how to get kappa.

Dear Axel
Thanks a lot for quick response. As per your suggestion i looked into the information given in the README file and corresponding input and log file of the examples/KAPPA folder but unfortunately i couldnot understand how the dQ values has taken from the log file.