How efficient is VASP for calculating the optical properties of nanoclusters with high vacuum spacing?

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purbajyoti_bhagowati1
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How efficient is VASP for calculating the optical properties of nanoclusters with high vacuum spacing?

#1 Post by purbajyoti_bhagowati1 » Fri Oct 01, 2021 11:23 am

VASP provides the calculation of the optical properties of materials using IPA, RPA and BSE methods. Does it work efficiently for small nanoclusters having large vacuum spacing?

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Re: How efficient is VASP for calculating the optical properties of nanoclusters with high vacuum spacing?

#2 Post by henrique_miranda » Tue Oct 05, 2021 6:48 am

This question is a bit vague but I will try to give some insight.

Because VASP is a plane-wave-based code the size of the basis increases with the volume of the cell you are using.
As such, increasing the vacuum will increase the cost of your computation.

Normally you should perform a few calculations with different vacuum spacing (first the calculations with a small vacuum and then with a larger vacuum) until your final results don't depend anymore on the vacuum size. The idea is to use the smallest vacuum possible (so the calculations are fast) that accurately represents your system.

Hope this answers your question.

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