科研之友
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摘要
Three stable, neutral diradical model molecules with an even number of electrons, based on pairs of small thiolated Au clusters connected via Au-Au bonding, are studied within a broken symmetry unrestricted density functional theory involving a set of exchange-correlation functionals, including PBE, M06L, TPSS, B3LYP, M06, and TPSSh. The models, mostly with an antiferromagnetic ground state within the theory used, are analyzed in terms of the vertical spin-flip energy splitting, total spin expectation values, Heisenberg exchange coupling constant, magnetic orbitals and their overlap, diradical character, binding energies, natural bond-order analysis, and bond index of the central Au-Au bond. The spin-symmetry breaking is attributed to the open-shell nature of the dimerized monomer constituents and the structural feature of the facing S-Au-S edges, in combination with the attractive unsupported metallophilic d-d interaction of the incident Au atoms, allowing a weak coupling of the spins localized sideways. The modeling provides insight to Au-1-Au-1 interactions, potentially useful in design of novel gold-based magnetic nanoscopic assemblies.
- 出版日期2012-8-23
- 单位中国科学院电工研究所; 南阳理工学院
