Question on "soft potential to remove atom overlap"

Dear members,

As suggested by Axel.K, I am posting my script file and reference papers
so that it could evolve into tutorial for others as well.

Below I describe the physical problem and the status of my attempts:

Physical problem:

1. The goal is to simulate argon flow around cnt, and study the drag on
    following reference papers 01, 02 ( details inside script file)

        a. Paper_01: "Drag on a nantube in uniform liquid argon flow",
                             W. Tang and S. Advani, J. Chemical phys., 2006.
        b. Paper_02: "Molecular dynamics simulations of liquid flow in and
                            carbon nanotubes" , Nicholls, Borg and Reese,
ASME 2010.

2. As a first step, I want to setup a NVT ensemble of argon around cnt.
    My lammps script file for it enclosed below:
    a. argon_cnt.script is the lammps script file.
    b. The script files reads cnt data from ; that cnt was
created using VMD.

3. Simulation domain size, argon, and cnt data are from paper_01.
   a. Liquid argon: T = 95 Kelvin ; Density = 1342 kg/m^3

   b. CNT: (12,0)-zigzag ; Diameter 9.422 angstroms ; Length = 21.3 angs.

   c. Domain size: x = 305.6 angs ( flow direction ; flow normal to cnt
axis )
                            y = 254.7 angs ( cross-flow direction )
                            z = 21.3 angs ( channel width -- also length
of CNT and cnt axis )

   d. Other data ( LJ potential for argon, carbon ) are from paper_01.

4. Used another paper_03 to test nvt simulation of argon bulk properties.

       [ "Equilibrium molecular dynamics studies on nanoscale fluids"

       Barisik & Beskok ; in Microfluid Nanofluid, 03 April 2011 ]

     a. I ran this case and the results are ok.

argon_cnt.script (16.3 KB) (11.7 KB)