Real Time calculation errors...

[sitangshu]

Dear Alejandro,

I am now capable to run BSE-DG/phonons/etc. Thanks to the YAMBO team!
I have some questions about the real time computational scheme. Already I went through the papers of Claudio A and Andrea M to understand what is actually going on with this computations. I then started the calculations for Si. The followings are the queries:
1. The gkkp electron-phonon calculations seems to be done on regular grid rather than the random points. If I do with the random points will that be OK, Since, the basic theory tell to use the random numbers over BZ. Further the code doesn't seem to generate ndb.elph* , but someway I figured it out how to do that.
2. I did not find this run level in yambo_rt : -v hsex for collision and -s p -q p for e-p scattering (-e and -p are there but not their <opt>). I guess, instead of -s it should be -c ?
3. Since there are much less details I am wondering, what DBsIOoff = "J G" means. Similarly, for "ALLGHAR"

Please guide me, so that I can go further with this calculations.

Regards,
Sitangshu

[amolina]

Dear Sitangshu,
the real time modulus (yambo_rt) is not yet released. Once yambo_rt enters in the GPL version of yambo we will published a more detailed documentation.
Best,
Alejandro.

[sitangshu]

Dear Alejandro,

Thanks for your reply. I saw that using recent gitpull one can make the rt executables. Infact I was able to figure out the graph of TD BSE and energy for Si (for delta-like pulse). However, it is the next command yambo -q p -s p which is paining me...

Regards,
Sitangshu

[Davide Sangalli]

Dear Sitangshu,
just to confirm that yambo_rt is in the last yambo release, but the only available option is TD-SEX, without any scattering.
You should be able to run it and then use ypp_rt yo post process the polarization to obtain the equivalent of the BSE spectrum as described here:
https://journals.aps.org/prb/abstract/1 ... .84.245110

The GPL version of yambo_rt is still experimental.
In the future we will extend its capabilities.

Best,
D.

[sitangshu]

Dear Davide,

Thanks for your reply. Incidentally, I already went through the paper you mentioned. Thats a bible.
Actually there is a command line: "ypp_rt -n o b -V all" for post processing in the script ypp_rt_si. I am using 4.2.1 version rev 110. But I am not getting these -n o b run levels...
Can you please correct me...

Regards

Sitangshu

[Davide Sangalli]

Dear Sitangshu,
below how it should work with the GPL version.

Step A: real time calculation

Code: Select all

yambo_rt -b -q -F yambo_rt.in
yambo_rt -F yambo_rt.in -J RT_dynamics -C RT_dynamics

Step B: post-processing of the polarization to generate eps(w)

Code: Select all

ypp_rt -t X -F ypp_rt.in
ypp_rt -F ypp_rt.in -J RT_dynamics -C RT_dynamics

Hope it helps.
Best,
D.