Matching formula items of a force field with that in LAMMPS

I am a new user of LAMMPS, and I hope I can get some important suggestions on the use of LAMMPS from you.

  1. How can I exactly match each formula item of a force field with the commands of LAMMPS (i.e., bond_style, angle_style,…)? In other words, how to use the exact formula of a force field in LAMMPS. Of course, it is not difficult to match some of them such as the bond and angle ones, but there are usually some special formula items in a force field. For example, there are 11 items in the CVFF including the 1st-4th items (bond lengths, bond angles, torsion angles, and out-of-plane interactions), 5th-9th items (off-diagonal/cross), and 10th-11th ones (non-bond interactions). However, there only to be the limited numbers of the _style commands in LAMMPS, as well as the formula forms included. How can I express the out-of-plane interactions, does it mean the improper_style? Furthermore, how should the off-diagonal items in CVFF be expressed by the LAMMPS commands, anyway, I did not find the corresponding formula forms in LAMMPS.

  2. When I use the read_data, need I delete all ‘coeff’ items in the .data file and only keep the atomic coordinates in it, and then define the 'coeff’s in the .in file?

Your answers and suggestions are very appreciated!
Shi-Chao Qi
College of Chemical Engineering,
Nanjing Tech Univerity,

Nanjing, China