Dear LAMMPS developers，

I wanna ask you two questions about MEAM potential library file.

The 1^{st} one: could I add a new line in the potentials/library.meam file for other elements？

The 2^{nd} one: how to determine “rozero” and “ibar”.

I’ve noticed that your previous mail in the website described as follows:

“> --> Rozero is called the (relative) density scaling parameter. It is only important for multi-component systems and is irrelevant for single element systems.

```
> --> Ibar decides which formula is used on the gamma function, which combines the partially electron densities, before calculating the embedding energy.”
```

References: http://lammps.sandia.gov/threads/msg11851.html

The last two parameters have confused me a lot. What’s the default value of rozreo for single element systems, 1.0 or other value? What’s the relationship between rho0(i) in the “lib\meam\meam_dens_final.F” file, Equ. 4.3 rho0 and rho chapter of “Numerical Tools for Atomistic Simulations, ?

“ibar”is a selection flag for computing G and dG in file “lib\meam\meam_dens_final.F”. ibar==0 or 1 or 2 or 3 or 4. Different values mean different G formula. I wanna know how to determine the value of ibar or which G formula I should choose. Are there some differences between multi-component systems and single elements systems while choosing the ibar value from 0, 1, 2, 3 and 4?

I have checked Baskes’s previous articles in the references, but these articles have no details about “rozero” and “ibar”. My intereted materials are Be and C.

I’m looking forward to your reply soon. Thanks very much!

Best regards,

CHIAO Kuaixiuan

GUCAS

, PRChina

PS:

[1] H. C. Huang, N. M. Ghoniem, J. K. Wong, and M. I. Baskes. Molecular-dynamics determination of defect energetics in beta-SiC using 3 representative empirical potentials.

*Modelling Simul. Mater. Sci. ,* 3(5):615-627, 1995.

** ***Rho0 **is the composition-dependent electron density scaling Equ.6

[2]M. I. Baskes. Determination of modified embedded atom method parameters for nickel.*Mater. Chem. Phys.,* 50(2):152-158, 1997.

***where A is an adjustable parameter and p. is a density scaling parameter. For this work (f.c.c. reference structure) po= z= 12. Equ.7