Hi,
I am trying to perform a series of Ti L-edge XAS calculations for SrTiO3 using the ICORELEVEL module available in VASP using an HSE06 xc functional. Since spin-orbit coupling (and therefore multipole splitting) is important when simulating the Ti L-edge, I believe only ICORELEVEL=1 (the initial state approximation) can be used. I am using the GW POTCAR files. I've also observed that the output spectra strongly changes every time I perform the calculation, regardless of initial configuration, and do not match well with a previous report: https://journals.aps.org/prresearch/abs ... h.5.013199. Would someone be able to help me with identifying what could be improved here?
Here is my input file:
LHFCALC= .TRUE.
AEXX = 0.25
HFSCREEN= 0.2
ALGO = All
PRECFOCK = FAST
HFLMAX = 4
LDIAG = .TRUE.
LSUBROT = .TRUE.
ENCUT = 520
NELM = 200
EDIFF = 5E-6
PREC = Accurate
LWAVE = .TRUE.
LASPH = .TRUE.
LREAL= .FALSE.
LMAXMIX = 4
ISMEAR = 0
SIGMA = 0.05
LORBIT = 11
ICORELEVEL = 1
CLNT = 2
CLN = 2
CLL = 1
CLZ = 1.0
CH_LSPEC = .TRUE.
CH_SIGMA = 0.001
CH_NEDOS = 2500
LSORBIT = .TRUE.
NBANDS = 208
NCORE = 4
Additionally, I wanted to run a benchmark and compare to a GW+BSE core level calculation for the Ti L-edge as was done in the attached report. I haven't been able to find any documentation for how to approach these types of calculations via VASP, though I have been able to find one report doing so for some K-edge spectra: https://arxiv.org/abs/2206.11544 I would appreciate any assistance on this end too. Thank you!