bare Coulomb matrix

[alvert92]

Dear Yambo community,

I was wondering whether there is a straightforward way of printing the matrix elements <cvk|v|c'v'k'> of the bare Coulomb interaction in Yambo. I found this post: viewtopic.php?f=10&t=1399 where printing the screened Coulomb matrix W is discussed, by modifying K.F . Therefore, I assume it must be possible to print out the bare Coulomb matrix as well. Unfortunately I was not able to figure out how to do it by looking through the K.F script. Could you please advise? Many thanks in advance.

Antonios

[Daniele Varsano]

Dear Antonios,
in the post you mention H_c are the screened potential matrix elements while H_x are the bare Coulomb matrix elements. Note that in the BSE the bare coulomb potential enters without the head (G=0) component.

Another way to extract them without changing the source could be to perform a BSE calculation including the exchange part only in the kernel and then read the netcdf databases with an external script (e.g. python).

Best,
Daniele

[alvert92]

Dear Daniele,

many thanks, this is very helpful.

Best regards,

Antonios