Update (June 10, 2019)

We have implemented DRIP as a LAMMPS built-in model, and it is available since the 5Jun19 version. Note

• It is in the USER-MISC package, so you need to add it when installing LAMMPS
• Examples at lammps/examples/USER/misc/drip/ or you can find it here
• Google lammps pair drip to get documentation

Original post (March 10, 2019)

The DRIP (Dihedral-angle-corrected registry-dependent interlayer potential) provides an improved description of the interlayer interactions for multilayer graphene structures. See our paper for more information about it. We have implemented the DRIP as a KIM model. To use it, follow the below instructions.

KIM-API

Follow https://openkim.org/kim-api/ to install kim-api-v2-2.0.0.

The instructions given there assume you have root access and install the API to /usr/local. If you do not have root access or want to install to another directory, follow INSTALL in the kim-api-v2-2.0.0 package.

Note, if you chose not to install the kim-api-v2-2.0.0 package in the standard location, you will need to get the kim-api library on PATH by doing some thing like (assume you are using Bash):

$ source activate path/to/the/installed/kim-api/library/bin/kim-api-v2-activate

DRIP driver and model

The DRIP driver and model can be obtained from my GitHub. The "v2.0.0" branch of both the driver and model is compatible with kim-api-v2-2.0.0. Below is a quick way to install them.

install the driver

$ git clone --branch v2.0.0 https://github.com/mjwen/DRIP_WenTadmor__MD_000000111111_000.git
$ kim-api-v2-collections-management install user ./DRIP_WenTadmor__MD_000000111111_000

install the model

$ git clone --branch v2.0.0 https://github.com/mjwen/DRIP_WenTadmor_2018_C__MO_000000111111_000.git
$ kim-api-v2-collections-management install user ./DRIP_WenTadmor_2018_C__MO_000000111111_000

To check that the driver and model are successfully installed, do:

$ kim-api-v2-collections-management list

You should be able to see DRIP_WenTadmor__MD_000000111111_000 and DRIP_WenTadmor_2018_C__MO_000000111111_000. in the User Collection.

LAMMPS (optional)

To use KIM with LAMMPS, you will need pair_kim. For now please put pair_kim.cpp and pair_kim.h into your LAMMPS src directory (we have made pull request to LAMMPS and the next official release of LAMMPS will be compatible with KIM), and then make LAMMPS the usual way you do.

pair_kim now only supports atom_style atomic, so please use it in your LAMMPS input script. DRIP only provides the interlayer interactions, so if you want to use it together with a potential that provides the intralayer interaction (REBO for example), you can use the hybrid/overlay pair style and put in the LAMMPS script the following lines:

pair_style   hybrid/overlay kim DRIP_WenTadmor_2018_C__MO_000000111111_000 rebo
pair_coeff   * * kim C
pair_coeff   * * rebo CH.airebo C

Note, we implement the DRIP potential in KIM using a different approach from the KC potential in LAMMPS. In the KIM implementation of DRIP, we have a method to separate the simulation configuration into layers automatically. So there is no need to assign atoms into different molecules as the LAMMPS KC implementation.