Theoretical studies of intra- and inter-magnetic interactions in TMAO(1, 3, 5, 7-tetramethyl-2, 6-diazaadamantane N, N '-dioxyl)

Ferromagnetic properties of TMAO organic crystal, especially alpha-form cry stal, are studied theoretically. There are two nitroxide groups, that is, b oth intramolecular magnetic interaction in one molecule and inter-molecular interaction between two molecules are expected in contrast to many organic ferromagnetic crystalline species that have been reported by other groups. Obtained J(ab) values for intra- and inter- molecular interactions are pos itive and small positive for only a few pairs, respectively. Cooperation of two types of magnetic coupling is essential to realize bulk ferromagnetic behavior.