# [lammps-users] related to lj units

Dear lammps users,

I have the following input file.I am working in lj units. I save in file
tmp.profile the variable v_temp. It still will be in units of energy.
How can I convert it to temperature units(in lj units)?
Furthermore, are there any error related to lj units after unfix 2?
I want to calculate the thermal conductivity in lj units. I think this is possible.

İput file

units lj

atom_style ellipsoid

lattice sc 0.01

region box block 0 8 0 8 0 16

create_box 1 box

create_atoms 1 box

set group all quat/random 18238

mass 1 1.0

shape 1 1 1 3

compute rot all temp/asphere

group spheroid type 1

variable dof equal count(spheroid)+2

compute_modify rot extra \${dof}

velocity all create 3.1 87287 loop geom

pair_style gayberne 1.0 3.0 1.0 4.0

pair_coeff 1 1 1.0 1.0 1.0 1.0 0.2 1.0 1.0 0.2

neighbor 0.8 bin

timestep 0.002

thermo_style custom step temp etotal vol epair press pe

thermo 100

fix 1 all npt/asphere 3.1 3.1 0.5 xyz 0.0 8.0 0.5

compute_modify 1_temp extra \${dof}

run 100000

unfix 1

fix 2 all npt/asphere 3.1 3.1 0.5 xyz 8.0 8.0 0.5

compute_modify 2_temp extra \${dof}

run 100000

unfix 2

fix 3 all nve

fix 4 all thermal/conductivity 100 z 20

thermo_style custom step f_4 temp press etotal

thermo 100000

compute ke all ke/atom

variable temp atom c_ke[]/1.5

fix 5 all ave/spatial 1 99000 100000 z lower 0.05 v_temp &

file tmp.profile units reduced ave running

run 2000****000

How can I convert it to temperature units(in lj units)?

3/2 k T = 1/2 m v^2 = KE and k = 1 in LJ units

Steve

2009/9/21 ahmet yıldırım <[email protected]...>:

Then,What will I receive the value of v(velocity)?
k=1
m=1
v=?
T=?

21 Eylül 2009 16:57 tarihinde Steve Plimpton <[email protected]> yazdı:

Dear lammps users,

I have the following input file.I am working in lj units. I save in
file
tmp.profile the variable v_temp. It still will be in units of energy.
How can I convert it to temperature units(in lj units)?

how do you convert kinetic energy to temperature in general?
for the specific example, keep in mind that in lj units the
kinetic energy is computed per particle by default unless
you use "thermo_modify norm no".

Furthermore, are there any error related to lj units after unfix 2?

please keep in mind that nobody here has the time to
do _your_ work for you. a mailing list is no replacement
for learning how to do research.

I want to calculate the thermal conductivity in lj units. I think this
is possible.

units are just units. if you can do something in one set of units,
you can do it in a different set. you just have to pay attention
to what quantity means what in any set of units.

cheers,
axel.