  We have shown that the observed large reduction of the effective moment and
the drastic violation of the Curie-Weiss law in Na2V3O7 (Phys. Rev. Lett. 90
(2003) 167202) is caused by conventional crystal-field interactions and the
intra-atomic spin-orbit coupling of the V4+ ion. The fine discrete electronic
structure of the 3d1 configuration with the weakly-magnetic Kramers-doublet
ground state, caused by the large orbital moment, is the reason for anomalous
properties of Na2V3O7. Moreover, according to the Quantum Atomistic Solid-State
Theory (QUASST) Na2V3O7 is expected to exhibit pronounced heavy-fermion
phenomena at low temperatures.
  PACS: 71.70.E, 75.10.D
  Keywords: crystal-field interactions, spin-orbit coupling, orbital moment,
Na2V3O7
