[lammps-users] force interaction

You can compute fij between two atoms from a compute (for example)
by calling pair->single().

Steve

Dear Steve

I can find in the src folder two folders pair_lj_cut and pair pair_lj_cut coul and fpair in them. But I do not know how these routins call. I want to add a routine to LAMMPS and I need fpair including lj+coul interactions. Would you please help me?

Regards

Saly

Hello, Saly:

Is this another attempt at addressing the same line of questioning you have pursued multiple times over the last two months in order to calculate a quantity that multiple people have told you is not well-defined? If so, perhaps you need to do an exploration of the literature to see what other people have done to calculate this quantity.

There’s a wonderful quote attributed to Frank Westheimer that you need to learn: “A month [of programming] saves an hour in the library.” There are other routes to calculating the surface tension that are readily available in the scientific literature that you could have used and been finished by now, instead of continuing this quixotic pursuit of ill-defined computations.

–AEI

Dear Axel

I read alot papers and the following book

“The molecular theory of capilarity”

For calculation IFT, fij is important certainely.

Also I emailed to the authors of the following paper that calculation of interfacial tension usng LAMMPS is performed in it. The authors said also we must calculate fij but it is not available in LAMMPS. They modified LAMMPS. Therefore I must change my simulation sofware (for example to GROMACS) or add a routine to calculate IFT. As I said before I found fpair in the routins. I should call them and use them for my purpose. Would you please help me?

Molecular Dynamics Study of a Surfactant-Mediated Decane

-Water Interface: Effect of

Molecular Architecture of Alkyl Benzene Sulfonate

Saly

Dear Axel

I read alot papers and the following book

but obviously not this paper:
http://dx.doi.org/10.1021/jp101860v

a.

Or:

http://dx.doi.org/10.1021/jp068767m

Or:

http://10.1063/1.2770730

–AEI

Dear Saly,

There are many ways to compute surface tensions, some of them much
simpler than the one you intend to use. For instance, see (among many
others) the following papers:

http://jcp.aip.org/resource/1/jcpsa6/v126/i15/p154707_s1
see eq (1): you only need to measure the total (average) normal and
tangential pressures.

http://jcp.aip.org/resource/1/jcpsa6/v126/i22/p221101_s1
the formula is in the introduction

http://pubs.acs.org/doi/abs/10.1021/la901314b
in the contact angle part, just after eq (2)

Best,
Laurent

Dear Friends

Thanks alot for your help for IFT calculation. Now I can measure IFT, but I need to calaculate the force between 2 nanoparticles to investigate solvation force and stability of a nanofluid. In this situation do you have any suggestion? Should I use the other package or in LAMMPS I can calculate the force?

Thanks alot for your time and attention

Regards

Saly

How about the compute group/group command?

Steve