Down scaling the parameters

LAMMPS LAMMPS Beginners
1

I am currently simulating Selective Laser Melting (SLM) at the nano scale and intend to downscale some of the parameters to establish a correlation between real-life scenarios and the nano-scale model (units :metal).

  1. The real-life SLM employs a laser power of 400 W. What could be the corresponding power in ev/ps. I am aware that a direct conversion from watts to ev/ps might result in an excessively high value, whereas others researchers have used 400-800 ev/ps (fix heat command).
  2. Similarly, the real-life SLM has a scan speed of 2000 mm/s. If I convert this to Å/ps, the value becomes 0.002, which seems considerably lower than values used by previous researchers . (moving region command).

I would appreciate any clarification or help

2

2000 mm/s = 2 m/s = 2·10-10/10-12 Å/ps = 200 Å/ps = 0.2 Å/fs

3

But that energy is distributed over an area. It will not be put into a single atom. So you would need to see how well that laser is focused and thus what its impact area is (I would also not expect that area to be impacted equally strong throughout, but would use that as a first order approximation). Then from it you can determine how many atoms fit into that area and from that how much of the energy is transferred to each atom. That will likely still overestimate the energy per atom, since you’ll also have to consider how deep the laser will penetrate.

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