Generic solution for hydrogen-antihydrogen interactions
  An internal inconsistency with mutually exclusive Hamiltonians and the corresponding mutually exclusive states HH and H-antiH suffices to doubt the usefulness of ab initio calculations for H-antiH based on 1927 Heitler-London theory. Removing this inconsistency in a generic way invalidates this theory but the compensation is that problems with antihydrogen are removed. 
G. Van hooydonk