Hi All,
I have a carbon nanotube (CNT) and Si block, in between I want to put a piece of other materials like polymers consisting of C and H. I want to model CNT, polymer using Airebo potential and Si using Tersoff potential, the interaction of polymer and Si block is characterized as LJ potential. C H Si are type 1,2,3 respectively in my data file. My input script as follows:
pair_style hybrid airebo 1.0 tersoff lj/cut 10.0
pair_coeff * * airebo CH.airebo C H NULL
pair_coeff 3 3 tersoff SiC.tersoff_optimized Si
pair_coeff 2 3 none
pair_coeff 1 3 none
pair_coeff 1*2 3 lj/cut 0.00213 1.506
The error is :
pair_style hybrid airebo 1.0 tersoff lj/cut 10.0
pair_coeff * * airebo CH.airebo C H NULL
pair_coeff 3 3 tersoff SiC.tersoff_optimized Si
ERROR: Incorrect args for pair coefficients
Can somebody tell me why I get such error and how can I get rid of it. I understand both tersoff and Airebo are manybody potential but I exclude the cross-term between 1*2 and 3. I thought it should work.
Any ideas or comments are highly appreciated.
Thanks,
Beneal
Hi All,
I have a carbon nanotube (CNT) and Si block, in between I want to put a
piece of other materials like polymers consisting of C and H. I want to
model CNT, polymer using Airebo potential and Si using Tersoff potential,
the interaction of polymer and Si block is characterized as LJ potential. C
H Si are type 1,2,3 respectively in my data file. My input script as
follows:
pair_style hybrid airebo 1.0 tersoff lj/cut 10.0
pair_coeff * * airebo CH.airebo C H NULL
pair_coeff 3 3 tersoff SiC.tersoff_optimized Si
pair_coeff 2 3 none
pair_coeff 1 3 none
pair_coeff 1*2 3 lj/cut 0.00213 1.506
The error is :
pair_style hybrid airebo 1.0 tersoff lj/cut 10.0
pair_coeff * * airebo CH.airebo C H NULL
pair_coeff 3 3 tersoff SiC.tersoff_optimized Si
ERROR: Incorrect args for pair coefficients
Can somebody tell me why I get such error and how can I get rid of it. I
understand both tersoff and Airebo are manybody potential but I exclude the
cross-term between 1*2 and 3. I thought it should work.
you thought wrong.
for manybody potentials you _always_ have to use: pair_coeff * *
you cannot "cancel" calculations after the fact with a "none" pair
style. this is not how lammps works. try this instead:
pair_style hybrid airebo 1.0 tersoff lj/cut 10.0
pair_coeff * * airebo CH.airebo C H NULL
pair_coeff * * tersoff SiC.tersoff_optimized NULL NULL Si
pair_coeff 1*2 3 lj/cut 0.00213 1.506
axel.