Section Linear Response::KdotP
If true, calculates second-order response of wavefunctions as well as first-order response. Note that the second derivative of the Hamiltonian is NOT included in this calculation. This is needed for a subsequent run in CalculationMode = em_resp with EMHyperpol.
sternheimer/kdotp.F90 : 474
call parse_variable(sys%namespace, 'KdotPCalcSecondOrder', .false., calc_2nd_order)