Yambo Community Forum

myrta gruning wrote:Hallo

About ypp there is no documentation, but using the command line
ypp -e <opt>
for generating the input is quite self-explaining, moreover the runs are fast (you can run it on your PC, is just post processing data).
You should start by sorting the excitation (opt=s), so that you know the numbers associated to each excitation (that you need to specify if you want e.g. to get the excitonic WF). Then you can analyze the amplitude (a option, this gives you the composition of the excitations in terms of KS transitions) or plot the exciton wave function (w option).

regards,
m

Well, I do struggle a bit with running ypp. I did the yambo calculation on a AIX cluster, and when I sync the data to my local machine for postprocessing, I cannot do anything since Running ypp on the cluster directly gives me segfaults, though the sorting seems to work but ypp -e a or ypp -e w give output files of 0 size...

Dear Bjoern,

Then there is another peak showing up in Im(eps) at lower energy. I thought, however, that the triplet should not show up in the absorption?

You are right, but I do not think that now you can interpret it as an absorption experiment. In this way you are decomposing the total exciton matrix in singlet and triplet part. Now you are diagonalizing the triplet block alone, and calculating the triplet excitations, anyway when you construct the epsilon2, surely you are not considering the singlet-triplet transition (which is the forbidden one!!). Actually, I should really read the paper I suggested you more carefully, and think about it!

Sorry for not to be exhaustive!!

Best,

Daniele


PS: about the ypp:

1) ypp -e s --> sort excitations
2) ypp -e a --> build the input file for analyzing excitation (to complete with the exciton index you get from o.exc_E_sorted produced before)
3) than run ypp

It works only if you have diagonalized with the "d" option and uncommented the option in order this option appear, you have to build your bse input with -V resp verbosity.