BSEPREC: Difference between revisions
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The timestep | The timestep in the time-evolution calculation is inversely proportional to the maximum transition energy {{TAG|OMEGAMAX}} and the number of steps is inversely proportional to the broadening {{TAG|CSHIFT}}. To make the algorithm sufficiently stable these parameters are scaled depending on the precision tag {{TAG|BSEPREC}}. | ||
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For example, the number of steps for {{TAG|BSEPREC}} = Low is <math>N_{\rm steps}=\frac{OMEGAMAXx2}{CSHIFTx5} | |||
Revision as of 09:13, 20 October 2023
BSEPREC = Low | Medium | High | Accurate
Default: BSEPREC = Medium
Description: BSEPREC determines the precision for the time-evolution calculation in BSE and TDDFT, i.e., the step size and the number of steps.
The timestep in the time-evolution calculation is inversely proportional to the maximum transition energy OMEGAMAX and the number of steps is inversely proportional to the broadening CSHIFT. To make the algorithm sufficiently stable these parameters are scaled depending on the precision tag BSEPREC.
BSEPREC OMEGAMAX CSHIFT Accurate (a) ×4 ×10 High (h) ×3 ×7.5 Medium (m) ×2.5 ×6.25 Low (l) ×2 ×5
For example, the number of steps for BSEPREC = Low is <math>N_{\rm steps}=\frac{OMEGAMAXx2}{CSHIFTx5}
Related tag and articles
NBANDSO, BSE calculations, timepropagation