Theoretical Studies of Magnetic Interactions in P-Cyanophenyl Nitronyl Nitroxide Crystal

• Published in: Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals Molecular crystals and liquid crystals, 1997-10, Vol.306 (1), p.331-338
• Main Authors: Oda, Akifumi, Kawakami, Takashi, Takeda, Sadamu, Mori, Wasuke, Hosokoshi, Yuko, Tamura, Masafumi, Kinoshita, Minoru, Yamaguchi, Kizashi
• Format: Article
• Language: English
• Subjects: Ab initio calculations; Atomic and molecular physics; Calculations and mathematical techniques in atomic and molecular physics (excluding electron correlation calculations); Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; Physics; Semi-empirical and empirical calculations (differential overlap, hückel, ppp methods, etc.); Statistical model calculations (including Thomas-Fermi and Thomas-Fermi-Dirac models)
• ISSN: 1058-725X
• DOI: 10.1080/10587259708044584

Magnetic interactions in crystal of p-cyanophenyl nitronyl nitroxide (p-CNPNN) were theoretically investigated. Semiempirical and ab initio molecular orbital calculations were performed for pair models of p-CNPNN molecules in the crystal. Effective exchange integrals (J ab ) are positive for the pairs of neighboring molecules in a sheet parallel to the ac-plane of the crystal, suggesting pseudo-two-dimensional ferromagnetic interaction in the ac-plane. Close contact between p-CN-phenyl group and NO group of the adjacent molecules plays a dominant role for the ferromagnetic interaction. Inter-sheet interaction is weak and the sign of J ab depends on the pairs.