pair style errors

Hello dear

Excuse me again.

Does anyone know of pair style errors?

I want to simulate water and nanofluid file contains just water not cu.i’ve defined cu in input code in a sphere region.(is it wrong??)

When it runs it shows this error “you must define pair style before pair coeff” .are pair style and pair coeff true.?sorry can anybody edit input code specially in term of pair style and pair coeff…thanks

Sincerely Mehdi.

Units real


group Water type 1 2

group oxygen type 1

group hydrogen type 2

group cu type 3


lattice fcc 3.610

region Cu sphere 0 0 0 7 units box

create_atoms 3 region Cu

group Cu type 3

set group oxygen charge -0.8476

set group hydrogen charge 0.4238

set group cu charge 0.000

pair interaction

#sigma=32.0e-11m epsilon=108.0e-21j

pair_style hybrid lj/cut/coul/long 32.0e-11 108.0e-21 eam lj/cut 32.0e-11

pair_coeff 1 1 lj/cut/coul/long 32.0e-11 108.0e-21 #32.0e-11 108.0e-21

pair_coeff 1 2 lj/cut/coul/long 32.0e-11 108.0e-21

pair_coeff 1 3 lj/cut/coul/long 32.0e-11 108.0e-21

pair_coeff 2 2 lj/cut/coul/long 32.0e-11 108.0e-21

pair_coeff 2 3 lj/cut/coul/long 32.0e-11 108.0e-21

pair_coeff 3 3 eam cu

bond_coeff 1 33.5315 3.3572

angle_coeff 1 2.181383 331.52

You need to set a pair style before reading data now, that is why you get the error I guess.

By the way, the values for your pair_coeffs are very strange. With “units real”, distances are in Ångstroms, not meters. Maybe you wanted to use “units si”?

A small addition: You only need to set pair_style before using “read_data” if the data file contains pair coefficiënts, which makes sense, as else LAMMPS would not know how to interpret these pair coefficients.


you are wasting your time. this person is beyond help. he obviously is fishing for somebody to do his thinking and his work for him. and doesn’t care if he annoys the hell out of people in the process. you are the third person to answer the identical question with the same information and nothing has worked. there are many more gross mistakes in this input that just prove that here is somebody that cannot work scientifically and extract useful information from documentation and advice being given.

he even went as far as posting from a different e-mail account (but with the same research topic and the same grammatical mistakes). anybody who thinks that people here a suckers of such magnitude, has forfeited any credit to get help.