ANTIRES = 0 | 1 | 2
Default: ANTIRES = 0
Description: The flag ANTIRES determines whether the Tamm-Dancoff approximation is used or not.
- ANTIRES=0 Tamm-Dancoff approximation (TDA)
- ANTIRES=1 yields exact results at ω=0 at roughly the same cost as TDA
- ANTIRES=2 beyond Tamm-Dancoff, coupling between positive and negative frequencies
VASP uses the procedures outlined in reference  to include contributions beyond Tamm-Dancoff. Beyond TDA calculations increase the computational time and memory requirements by typically a factor of 2.