How to exatract the upper surface's atoms' xyz coordinate values

Hello everyone,
Nowadays, there is a question making me puzzle. I just want to extract atoms’ xyz coordinate values which belong to the upper surface, But I have no idea. Any one who can give me some advice?
Thanks in advance.
Best regards.

Hello everyone,
Nowadays, there is a question making me puzzle. I just want to extract
atoms' xyz coordinate values which belong to the upper surface, But I have
no idea. Any one who can give me some advice?

there is no simple, single answer to such a generic question. please
keep in mind that the requirement to identify atoms is rather vague in
computer terms.

the best strategy depends on what you need this information for, what
kind of a system you have (solid or liquid), what kind of shape of a
surface you have, and finally when and how you need that information.
it can be as simple as defining a region in LAMMPS or a complex as
requiring implementation of a new C++ class in LAMMPS.

axel.

There are several ways to dump the coords of selected atoms
with the dump command. You can assign them to a group or

region or you can use the dump_modify thresh command
to limit the output, e.g. all atoms whose z coord > value.

Steve

Hello, Thanks for your reply,
What I want to do is to extact a surface’s atoms’ xyz. And the surface is just like:

(upper)
O O O O O O O O O
OOO OOO OOO OOO OOO OOO OOO OOO OOO
OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO
OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
(base)

I will try the advice you give. Thanks. Best Regards.

Thanks for your reply,
What I want to do is to exatract a surface’s atoms’ xyz. And the surface is just like:

(upper)
O O O O O O O O O
OOO OOO OOO OOO OOO OOO OOO OOO OOO
OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO OOOOO
OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO OOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
(base)

I will try the advice you give. Thanks. Best Regards.