Discrepancy between TDHF and TIMEEV
Posted: Sun Dec 17, 2023 12:17 am
I'm trying to compare the outputs of a set of time-dependent calculations on LiF using TDHF and TIMEEV algorithms. I'm using a global hybrid XC-functional (AEXX=0.5) in these calculations. (Vasp version 6.4.2; Intel compiler+MKL)
From running a few tests, it appears that, minimally, one has to explicitly set LADDER=.TRUE. for the TIMEEV case otherwise it just reproduces the independent-particle spectrum. With that done, the TIMEEV spectrum now seems to capture the energy of the first excitonic peak correctly but the height is quite wrong. The overall shape of the spectrum with TIMEEV is also quite different from the TDHF case.
My files are attached.
From running a few tests, it appears that, minimally, one has to explicitly set LADDER=.TRUE. for the TIMEEV case otherwise it just reproduces the independent-particle spectrum. With that done, the TIMEEV spectrum now seems to capture the energy of the first excitonic peak correctly but the height is quite wrong. The overall shape of the spectrum with TIMEEV is also quite different from the TDHF case.
My files are attached.