Optical matrix elements

[Daniele Varsano]

Dear Shudong,
double-check that you extracted the correctly the dipole moments, next if the results are not in agreement in the literature, maybe you want to consider to write to the authors.

Best,
Daniele

[Fadil]

Dear Shudong,
the script reads the dipole databases (ndb.dip_iR_and_P_fragment_*), i.e.
q.<v|r|c>
These are needed both in the IP response function and for the BSE spectra.

Best,
Daniele

Dear all,
The dipole matrix elements obtained from 'ndb.dipoles' are 'i*<v|r|c>' or 'i*q*<v|r|c>'? (where q0 = 10^-5 Bohr)
If the latter, the dipole values should be;
(the extracted value)/(i*q0)

Best

[Daniele Varsano]

Dear Fadil,

by default the ndb.dipoles files contains the <iR>, <P> e <v> quantities. No q0 is included there.
Best
Daniele

[Fadil]

Thank you for clarification Daniele.

Best

[lyzhao]

Dear all,
For yambo 4.5.3
I reactivate this post to make sure whether the DIPOLE* module of yambo have calculated the diagonal and intraband optical matrix elements,
such as p_v1v2, p_c1c2, and p_nn, where v =valence, c = conduction, n = any band.

I have noticed the DIP_P(:,iv,iv,ik_mem,i_sp_pol) in line 266 of DIPOLE_transverse.F
but I don't find the DIP_P(:,ic,ic,ik_mem,i_sp_pol)

Best regards.

[Davide Sangalli]

Dear Youzhao Lan,
I confirm that yambo, in some cases, computes DIP_P, DIP_v, and if possible also DIP_iR for all nm indexes.

Put

Code: Select all

DipBandsALL

in your input.

Best,
D.

[lyzhao]

Dear Davide Sangalli,
Thanks for your confirmation.

Best regards.

[lyzhao]

Dear Davide Sangalli,
Can I restrict the range of valence and conduction bands with DipBandsAll?
For example, I have 240 bands. By default, DipBandsAll leads to the dip calculations between 240 bands.
If I only want to calculate the dips between bands in the range of 40-200, is there a keyword for this?
I have tried the following input within an ipa calculation (yambo -o c ), but no effect

Code: Select all

% DipBands
   40 |  200 |                     # [DIP] Bands range for dipoles
%
DipBandsALL               # [DIP] Compute all bands range, not only valence and conduction

Best regards.
Youzhao Lan

[Davide Sangalli]

Yeah, you can.

Code: Select all

DipBands

determines the bands range you prefer.
The only requirement is that the first number is smaller or equal than the index of the last occupied band, while the second number is bigger or equal to the index of the first empty band.

Code: Select all

DipBandsAll

just imposes to compute also the CC (conduction-conduction) and VV (valence-valence) matrix elements, and not only the CV (conduction-valence) ones.

Best,
D.

[Fadil]

Dear all,

For the calculations of dielectric function or EELS with the finite momentum (q =/ 0), how can we extract '<nk| exp(i(q+G)r) | mk-q>' matrix elements as a function of n, m, q, G?

Best