QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: aschenk on June 21, 2012, 04:36
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Hi,
I'm currently running some STM/STS experiments, and want to generate some LDOS plots to compare to my dI/dV. I know dI/dV and LDOS aren't equal to one another, but there is a correlation.
I've put together a device system with the surface I'm interested in, and will be creating vacancies and defects in the surface structure, followed by a geometry optimisation, then calculating the LDOS. I've run a couple of LDOS calculations and it seems to be working, but now I want to cut out quite a bit of the work. Is there a script I can use which will run the LDOS calculation over a range of energies, so I can start just one calculation which will cover my range of interest, rather than having to initiate ~20 calculations, one after the other?
I've seen that there is a way to extract the LDOS at a particular grid point; how do I find the coordinates of the grid point(s) I am interested in so that I can add a script to extract just these values (as I only want to know the LDOS at the defect I induce), and can the fact that I am only interested in a few specific points be used to speed up the calculation in any way? I suspect the answer to this question will be no, due to the self consistent nature of DFT calculations, but I thought I would check.
Thanks very much
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You are correct about the final question. It's not really due to the self-consistent nature, but actually it would almost take the same time to compute a single point as the whole grid, due to the algorithms connecting the density matrix and the real-space grids.
You can however easily script your way out of setting up many individual calculations. Have a look at http://quantumwise.com/forum/index.php?topic=1279.0 which in fact also contains the answer to your question about the grid point coordinates :)