Quadratic static response functions

Figure 4. Static hypermagnetizability anisotropy. Atj(O), computed with the d-aug-cc-pV5Z basis set (Neon) and d-aug-cc-pVQZ basis set (Argon). Orbital-relaxed results obtained with a finite field approach from analytically evaluated magnetizabilities are compared to those obtained from orbital-unrelaxed quadratic and cubic response functions...

The quadratic response function is imaginary. In the static case to = 0 the quadratic response function is zero, as there are then no anti-Hermitian contribution to the first order response vectors. 

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