Abstract
Pairs of atoms in solid bcc have spatially symmetric or antisymmetric wave functions which correspond to energies and , . The energy difference is due to a tunneling process and an interaction process. The effect of these two processes can be simulated by adding to the Hamiltonian of the solid an exchange Hamiltonian, where is a sum (due to the tunneling process) and (due to the interaction process). A theory of the magnitude and sign of and is given. We find and . Using quite general arguments, we show that . The exchange in bcc solid is antiferromagnetic. Evaluation of the formulas for and using the ground-state wave function of Guyer and Sarkissian leads to , in good agreement with experiment.
- Received 17 October 1968
DOI:https://doi.org/10.1103/PhysRev.188.445
©1969 American Physical Society