[lammps-users] Error in coupling Tersoff potential for amorphous SiO2

Hi,

I am looking to couple amorphous SiO2 with a tersoff potential.

I am currently using the one suggested by Zhun-Yong in one of the previous mail lists.
I get an error saying: potential file is missing an entr****y.

I define the tersoff potential in the input file as:

read_data data.silica

pair_style tersoff
pair_coeff * * SiO2.tersoff Si O

Is this the right method to couple the tersoff potential?

The potential file I am using is the one suggested by zong:

Si and O mixture, parameterized for Tersoff potential

this file is from [email protected]…1218…

values are from Munetoh et al, Comp. Mat. Sci. 39, 334-339 (2007).

Tersoff parameters for various elements and mixtures

multiple entries can be added to this file, LAMMPS reads the ones it need=

s

these entries are in LAMMPS “metal” units:

A,B =3D eV; lambda1,lambda2,lambda3 =3D 1/Angstroms; R,D =3D Angstroms

other quantities are unitless

format of a single entry (one or more lines):

element 1, element 2, element 3,

m, gamma, lambda3, c, d, costheta0, n,

beta, lambda2, B, R, D, lambda1, A

O(M) O(M) O(M) 3.0 1.0 0.0 64692.1 4.11127 -0.845922 1.04968
1.1632e-7 2.35692 218.787 1.85 0.15
4.17108 1882.55

Si(M) Si(M) Si(M) 3.0 1.0 0.0 100390 16.217 -0.59825 0.78734
1.1000e-6 1.7322 471.18 2.65 0.15
2.4799 1830.8

Si(M) Si(M) O(M) 3.0 1.0 0.0 100390 16.217 -.59825 .78734
1.1000e-6 1.73222 471.18 2.21 0.15
2.4799 1830.8

Si(M) O(M) O(M) 3.0 1.0 0.0 100390 16.217 -.59825 .787340
1.1000e-6 2.04456 378.690 2.21 0.15
3.3305 1856.4947

O(M) Si(M) Si(M) 3.0 1.0 0.0 64692.1 4.11127 -0.845922 1.04968
1.1632e-7 2.04456 378.690 2.21 0.15
3.3305 1856.4947

O(M) Si(M) O(M) 3.0 1.0 0.0 64692.1 4.11127 -0.845922 1.04968
1.1632e-7 2.35692 218.787 1.9 0.15
4.17108 1882.55

O(M) O(M) Si(M) 3.0 1.0 0.0 64692.1 4.11127 -0.845922 1.04968
1.1632e-7 2.35692 218.787 2.21 0.15
4.17108 1882.55

Si(M) O(M) Si(M) 3.0 1.0 0.0 100390 16.217 -.59825 .78734
1.1000e-6 1.73222 471.18 2.65 0.15
2.4799 1830.8