Hello LAMMPS developers,
Although I can run a simulation with the command “fix_modify ATC fields add electric_potential” (LAMMPS 3 Mar 2020) without any problem, there is no description for the electric_potential field. Can you please add some information about it, for example, what the unit is?
Best,
Duc Tam
Please note that the project that funded the development of the AtC package does not exist anymore for quite some time, so there is no active development and thus nobody that would be around to do such updates. First order approximation of the unit would be the same units if you would compute the electrostatic potential of the (charged) atoms in your system, which will depend on the choice of units in LAMMPS (units command — LAMMPS documentation). If that seems inconsistent, the second place to look for information would be the comments in the source code (mostly in the lib/atc folder).
For more specific questions, you can try contacting the AtC package developers. Most of them will likely have retained their email addresses, which should be mentioned in the source code and README files related to the AtC package.
Hello, do you know what f_AtC[1] f_AtC[2] f_AtC[3] f_AtC[4] stands for
Please see the LAMMPS manual. Best start with this page
https://docs.lammps.org/Howto_output.html
and continue with the pages it refers to.
Hello, I couldn’t find a description of what f_AtC[1], f_AtC[2], f_AtC[3], and f_AtC[4] represent in the manual. Could you help me understand what they mean? The manual only has a few sentences about the fix atc command.
“f_” is a generic reference. Please follow my suggestions and you shall see. You cannot have read and understood all of that in less than 10 minutes.
Okay, thank you for your response. I must admit that I didn’t read it carefully. I just skimmed through to see if there was any description of f_AtC[1], f_AtC[2], f_AtC[3], and f_AtC[4], and I thought it would be like the fix ttm/mod command, which explicitly tells you that f_ttm[1] is the total energy of the electronic system and f_ttm[2] is the transferred energy.
For ATC things are not as straightforward, since what is done by fix atc largely depends on the fix_modify settings. Also, your question indicated that you didn’t understand what “f_” means rather than which specific values correspond to the various global vector values returned by fix atc. For that you have to carefully study the fix atc documentation and its (many) subcommands.
Please also note, that the development of the ATC package was stopped before it was completed due to lack of funding and thus its documentation may be incomplete or out of date and - apart from trivial fixes - no updates will be made. In fact, the LAMMPS developers have been discussing to remove it from the distribution for those reasons.