How to extract W(qx,qy)

[yhypku]

Dear developers,
I wonder how to extract screened Coulomb interaction W(qx,qy) value from a standard BSE calculation (just like the Extended Data Fig. 1 of Nature Nanotechnology 15, 367–372 (2020)). I have checked the database files but failed to find a clue. Thanks.
Best,
Huaiyuan

[Daniele Varsano]

Dear Huaiyuan,
the plot you are looking at represents the quantity
<cvk|W|cvk'> with k-k'=q
which is extracted from the direct term of the kernel of the Bethe-Salpeter equation.
This is not plotted by yambo and it has been obtained reading the terms of the kernel.

You can extract it by printing the H_c term and relative indexes in K.F:

Code: Select all

464          ! Correlations
465          if (BS_res_K_corr)     H_c=K_correlation_kernel(i_block,i_p,i_pmq, &
466 &                                   i_k_s,i_kp_s,i_c_k,i_c_p,i_kmq_s,i_kp_mq_s,i_v_k,i_v_p,     &
467 &                                   i_kmq_t,i_pmq_t,i_k_sp_pol_c,i_p_sp_pol_c,i_k_sp_pol_v,i_p_sp_pol_v,  &
468 &                                   iq_W,iq_W_s,ig_W,i_k_s_m1,iq_W_s_mq,ig_W_mq,i_kmq_s_m1)

Best,
Daniele