Can Induced Orbital Paramagnetism Be Controlled by Strong Magnetic Fields?

Magnetic hypersusceptibilities and hypershielding at the nuclei ofBH, CH$^+$, C$_4$H$_4$, and C$_8$H$_8$ molecule in the presence ofan external spatially uniform, time-independent magnetic field, have beeninvestigated accounting for cubic response contributions via Rayleigh-Schr{\"o}dingerperturbation theory. Numerical estimates have been obtainedat the coupled Hartree-Fock and density-functional levels of theorywithin the conventional common-origin approach, using extendedgaugeless basis sets. The fundamental role of electron correlation effects was assessed.Critical values of the applied magnetic field at which transitionfrom paramagnetic to diamagnetic behavior would occur were estimated.It is shown that perturbative methods may successfully be employed to estimate theinteraction energy for big cyclic molecules.