[lammps-users] What are the units used in angle_table file?

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1 
Dear Steve,
Could you explain a little bit why the unit of the "force" column is the LAMMPS force unit? 
Isn't the column -dU/d(phi)? I can understand that the corresponding column of the bond table has the unit of force. 

But I don't see how it is also the case for the angle table.
Thanks a lot.
Lanyuan Lu

The units should be those that LAMMPS uses
for energy and force, which depend on what units you
have set (lj, real, metal, etc).  See the doc page for

the units command for details.

Steve
2

You're right - the doc page should say it is -dU/d(theta).
The code further processes that quantity to get a force
on each of the 3 atoms (in force units). I probably
just copied the doc info from the bond table command
w/out thinking ...

I'll change the doc page next week.

Thanks,
Steve

3

Thanks, Steve. So is the unit (LAMMPS energy unit)/degree or (LAMMPS energy unit)/rad? This is actually the original question at the beginning of the thread.
Best,
Lanyuan

4

per-radian.

Steve

5

Just another question, is the first column (angle) in degree or radian? In the manual example, it’s in degree.
So in summary, the three columns should be:
theta U -dU/d(theta)
degree/rad? energy unit energy unit/rad

Thanks,
Lanyuan

6

sorry - this wan confusing due to the doc page,
which I just reposted. (but nothing changed in the
src code).

The columns are:
theta (degrees) energy (energy units) -dU/d(theta) (also energy units)

The last column is a derivative with respect to theta in degrees, not radians.

Steve