I am currently using Yambo and I am writing to ask what approximations Yambo uses to treat the divergence of the coupling term H_cvk_c'v'k' when W(G=0,G'=0) and c=c' (or v=v') and k=k' ?

On the documentation webpage http://www.yambo-code.org/doc/docs/doc_BSS.php, it is written

.It should be noted that some terms in the sums diverge if G, G prime and eventually q are equal to zero, this means that some tricks have to be used in order to cure these divergencies, altough it is beyond the scope of this introductory description of the Bethe-Salpeter to present these details, the interested reader can refer to Albrecth.

Can you explain how Yambo get around this divergence a bit more in detail ? Thanks in advance.

Jun Yan

CAMD, DTU

http://dcwww.camd.dtu.dk/~juya/