LRC_alpha

[vitoversace]

Dear Daniele,

1) should the value of LRC_alpha = -8.7 for LiF in the tutorial be changed
if i want to calculate MgO spectrum at TDDFT level or is this a fixed value for all materials ???

2) is it possible in TDDFT to get excitation energies and weights ( ypp -e s , ypp -e a ) like in bse ?
3) are there other types of TDDFT kernel which are based on mapping theory in yambo ?

Bests
Vito

[Daniele Varsano]

Dear Vito,
1) the LRC kernel you are referring it is not ab-initio, so alpha (which is somehow related to the screening) is a system dependent parameter.
2) Yes it is, if you do the calculation in the electorn-hole KS basis
3) Well, there should be the kernel extracted from the Bethe-Salpeter, so a long range one without empirical parameter (have a look to this paper and this. But I do not know if it is included in the GPL and anyway it gives you the same results of the BSE and the computational effort it is essentially the same.
Hope it helps,
Daniele