Section Linear Response::Polarizabilities
Do not use saved linear-response wavefunctions from a previous run as starting guess. Instead initialize to zero as in FromScratch, but restart densities will still be used. Restart wavefunctions from a very different frequency can hinder convergence.
sternheimer/em_resp.F90 : 992
call parse_variable(sys%namespace, 'EMWavefunctionsFromScratch', .false., em_vars%wfns_from_scratch)