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The flag ANTIRES determines whether the Tamm-Dancoff approximation is used or not. The allowed settings are:

ANTIRES=0 default: Tamm-Dancoff approximation (TDA)
ANTIRES=1 yields exact results at $ \omega=0$ at roughly the same cost as TDA
ANTIRES=2 beyond Tamm-Dancoff, coupling between positive and negative frequencies

VASP uses the procedures outlines in Ref. [118] to include contributions beyond Tamm-Dancoff. Beyond TDA calculations increase the compute time and memory requirements by typically a factor 2.

N.B. Requests for support are to be addressed to: