Potential file is missing an entry

Dear all,

I am using LAMMPS to simulate some thermodynamic properties of b-SiGe. I found the potential file in the official github repository for LAMMPS . The first part of my code is this

###############################################################
#1 general
units           metal
dimension       3
atom_style      atomic
neighbor        0.3 bin

#2 structure
boundary        p p p
read_data       lammps.dat
mass            1  28.09
mass            2  72.61
#3 variables
variable        temperature equal    1.0
variable        pressure equal 0.0
variable        tstep equal 0.001
variable        strainmax equal 0.5
variable        srate equal 1.e8/1.e12
variable        tmp equal bound(all,xmax)-bound(all,xmin)
variable        lenx equal ${tmp}
variable        vtension equal sqrt(${srate}*${srate})*${lenx}
variable        nstep equal ${strainmax}*${lenx}/${vtension}/${tstep}

#4 potentials
pair_style      tersoff
pair_coeff  * * SiCGe.tersoff      Si  Ge 
############################################################

However LAMMPS is showing this error -

Reading tersoff potential file SiCGe.tersoff with DATE: 2009-03-18
ERROR: Potential file is missing an entry (src/MANYBODY/pair_tersoff.cpp:550)
Last command: pair_coeff * * SiCGe.tersoff Si Ge

Can you please tell me what mistake I have made here ? Any help will be greatly appreciated .

Thanks,
Jobayer

Update : I was able to solve it when my accout was pending . Had to write Si(D) in the pair_coeff .

Please look at the contents and comments in the potential file. It doesn’t have any entries for “Si”, only for “Si(B)”, “Si(C)” and “Si(D)” and only the “Si(D)” entry is suitable for use in combination with “Ge”.

Dear Dr. Axel Kohlmeyer ,

I appreciate your swift reply . Thanks a lot !

Sincerely ,
Jobayer

FWIW, I felt that the error message was a bit too unspecific and could not be easily understood without looking at the source code (and then at the potential file).
I have now implemented a change to print for which combination of elements the entry is missing. That would hopefully motivate people to look at the potential file right away.
This change will be released in a future version of LAMMPS.

1 Like

Dr. Axel Kohlmeyer ,

That sounds great ! Looking forward to the next release .

Regards ,
Jobayer