Why ab-initio MD and at what temperature I have to take for potential generation?
Hi Sankhasubhra,
There are some reasons that people chose to train on ab-inition MD, I will list three that I think are really important:
Ab-initio MD provides a high level of accuracy by directly solving the electronic Schrödinger equation using DFT. This allows for precise calculations of energies, forces, and stress tensors. By doing that, you can create potentials that has DFT or close to DFT precision, and you can get the potentials to use larger cells in your calculations that can be hard to handle by DFT.
Flexibility is also important. Unlike classical force fields, which are typically restricted to specific material classes, ab-initio MD can be applied to all types of materials individually and in any combination.
Reactivity is also important, that is why DFT is famous in chemistry community. Ab-initio MD potentials are reactive force fields, capturing chemical reactions and bond-breaking/bond-forming events.
About the temperature, when generating potentials using ab-initio MD, you need to simulate the system at a specific temperature, as you mentioned. The choice of temperature depends on the material and the physical conditions you want to model. Commonly used temperatures include room temperature (around 300 K) or higher temperatures relevant to specific applications. For example, if you’re interested in studying phase transitions, melting behavior, or thermal properties, you might choose temperatures above room temperature. Usually if you want to study a specific phase of a material, you need to do the simulations in the temperature that the material is stable.
Remember that ab-initio MD simulations involve solving the equations of motion for atoms using quantum mechanical forces obtained from DFT calculations.
I hope it helps,
Igor Evangelista
Using ab initio molecular dynamics (AIMD) simulations based on density functional theory (DFT) for generating forces and final atomic coordinates is a common approach in the development of Embedded Atom Method (EAM) potentials for several reasons:
Overall, leveraging AIMD simulations in DFT for generating forces and final atomic coordinates provides a robust and reliable approach for developing EAM potentials that accurately capture the complex atomic interactions in materials.
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