Oscillator Strengths in EPW
Posted: Sat Feb 28, 2026 9:09 am
Dear all,
I am running a GW-BSE-EPW workflow to compute exciton-polaron optical spectra. I have completed the following stages:
- BerkeleyGW: epsilon → sigma → kernel → absorption (Q=0 and finite-Q BSE)
- EPW Step 1: electron-phonon Wannier interpolation (epw1.in)
- EPW Step 2: exciton-polaron optical spectra (epw2.in)
In BerkeleyGW, the absorption.x code outputs eigenvalues.dat, which contains the exciton energies and oscillator strengths for each eigenstate. This allows me to directly identify bright vs dark excitons.
How do I obtain the oscillator strengths in EPW?
Best regards,
Agathyan
P.S.: Here is the input for epw2.in
I am running a GW-BSE-EPW workflow to compute exciton-polaron optical spectra. I have completed the following stages:
- BerkeleyGW: epsilon → sigma → kernel → absorption (Q=0 and finite-Q BSE)
- EPW Step 1: electron-phonon Wannier interpolation (epw1.in)
- EPW Step 2: exciton-polaron optical spectra (epw2.in)
In BerkeleyGW, the absorption.x code outputs eigenvalues.dat, which contains the exciton energies and oscillator strengths for each eigenstate. This allows me to directly identify bright vs dark excitons.
How do I obtain the oscillator strengths in EPW?
Best regards,
Agathyan
P.S.: Here is the input for epw2.in
Code: Select all
--------
&inputepw
! General Flags
prefix = 'AA'
outdir = './'
dvscf_dir = './save/'
! Core EPW Control Flags
elph = .true.
epbwrite = .false.
epbread = .false.
epwwrite = .false.
epwread = .true.
etf_mem = 0
! Wannier Basis Flags
wannierize = .false.
nbndsub = 9
use_ws = .true.
asr_typ = 'crystal'
eig_read = .true.
! Exciton-polaron flags
lpolar = .true.
exciton = .true.
explrn = .false.
negnv_explrn = 1
nbndv_explrn = 13 ! Match the valence band in BSE calcs.
nbndc_explrn = 87 ! Match the conduction band in BSE calcs.
init_plrn = 1
niter_plrn = 500
! Optical Absorption Flags and Energy Parameters
lindabs = .true.
omegamin = 0.05
omegamax = 10.00
omegastep = 0.01
fsthick = 11.0 ! eV
temps = 0 100 300 ! K
degaussw = 0.05 ! eV
efermi_read = .true.
fermi_energy = -2.412092
elecselfen = .false.
phonselfen = .false.
a2f = .false.
! Brillouin Zone (BZ) Grid Flags (Fine Grids)
nkf1 = 60
nkf2 = 60
nkf3 = 1
nqf1 = 60
nqf2 = 60
nqf3 = 1
nk1 = 10
nk2 = 10
nk3 = 1
nq1 = 10
nq2 = 10
nq3 = 1
mp_mesh_k = .true.
/