Feuston Garofalini potential

Dear Lammps users,
I’ve been using LAMMPS for a year. Thanks to this mailing list, I learned a lot of thing and still I have been learning:) Thank you for your contribution to me:)

My research is about Ge on insulator which contains following atoms: La,Si,Ge and O.Therefore I need to find proper potential to describe all these interactions in LAMMPS format.

Garofalini potential seems to most proper for my research materials.

I met following message in LAMMPS forums (http://lammps.sandia.gov/threads/msg28578.html), this message made me very happy:) but I couldn’t find another information about Garofalini potential in the mailing lists:(

I need your help about garofalini potential, I will be very very happy if you help me:)

I want to implement Garofalini potential into LAMMPS code. But in Garofalini potential, there is “complementary error function”. According to my research, this erfc function is used as switching function, instead of Ewald method.

Wolf method seems to be consistent with Garofalini potential due to complementary error function in potential according to LAMMPS tutorial (http://lammps.sandia.gov/doc/pair_coul.html). But wolf method contains real space term in addition to reciprocal space terms that is, there exist error function in addition to complementary error function in wolf method.

Can I use the wolf method? If I can, how can I eliminate error function in order to obtain correct Garofalini potential including only complementary error function?

If I use wolf method for exact garofilini potential definition, I think I need to implement following command into my input file.

pair_style born/coul/wolf alpha cutoff

Is it corrent expression for garofalini potential? Is there anyone else using Garofalini potential in him/her research?

How can I do in order to use garofalini potential in LAMMPS format. I couldn’t correctly describe this potential using pair_style command in input file.

​I would be very happy if you can help:)

​With my best regards,

Ray can comment on using the Wolf potential for FG. He is CCd.

I don’t know of anyone who has implemented FG for LAMMPS.

You can ask Ed Webb (Lehigh), also CCd, who I know has

worked with FG in the past.


FG potential is particularly efficient when tabulated. So what about to rather use pair_table?

Xavier Bidault

I answer myself… Indeed i forgot the 3-body part. I had reworked the SW pair to make it lighter, to only have the 3-body part, the 2-body part being tabulated.