Hi,
I am trying to simulate a material in Gromacs. however, I am using parameters used in lammps.
There is a confusing part which is related to the bonds.
based on what I read from the article, the bond between Ti and O is at the length of 2.1 A (0.21 nm) and the force constant is 400 Kcal/mol (1673.6 kj/mol).
Now the question I have is that what type of bond it is.
I searched here as well but so far haven’t been successful to understand it.
I would be very appreciative if someone could help me understand this.
The information you seek should be in the article that you are trying to reproduce (if it is properly done). Or you should contact the authors for the details.
Thank you.
All I am confused about is that how these parameters can be implemented in lammps so that id be able to figure out what alternative is in gromacs
All the available bond styles in LAMMPS are listed in the documentation, but the information which one is used must be in the paper you are looking at. It cannot be known without knowing the description of the model in the paper.
Hi thanks.
I read the article and they mentioned that those values are for harmonic bonds.
However, the potential from harmonic is U = K (r-r0)^2. meaning, K (spring constant) is energy.distance^-2. In the article, they mentioned that the force constant is 400 Kcal/mol, which this is energy unit.
how is this possible to use it in lammps?
We are going in circles now. The information you need will be in the paper you have before you or you need to get it from it’s authors.
Also consider that you may have misread something or that the authors made an error with the units.
No, I think I found the answer.
kcal/mol as the force constant, indeed is a scaled spring constant in Harmonic potential.
I am reading more about it.
I will share results here how to convert it.
Thanks
So here is the thing, https://www.ks.uiuc.edu/Research/vmd/current/ug/node237.html.
I think to get the spring constant as usually used in LAMMPS and GROMACS, I should do 400/(2.1^2), then k is kcal/mol.A^2