Diamagnetism of helium

The diamagnetic susceptibility of two helium atoms is calculated as a funct ion of atomic separation R and the spherical-average incremental susceptibi lity is evaluated. The Hartree-Fock approximation is used at intermediate s eparations and perturbation theory for the leading, 1/R-6, term in the incr ement at large separations. The change in average atomic susceptibility in liquid helium, relative to that for isolated atoms, is estimated. It is con cluded that measurements on the liquid may be used to accurately determine the isolated atom diamagnetic susceptibility. (C) 2000 American Institute o f Physics. [S0021-9606(00)30343-9].