“Obesity Paradox” or a Better Nutritional Status?

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• 作者：Brunella Guida ; Roberta Laccetti ; Alfredo Procino ; Bruno Memoli
• 关键词：Nickel ; Transition metals ; Impurity ; Hydrogen ; Oxygen ; Carbon ; Detachment energy ; Ionization potential
• 刊名：The American Journal of Medicine
• 出版年：2008
• 出版时间：July 2008
• 年：2008
• 卷：121
• 期：7
• 页码：e7
• 全文大小：53 K

文摘

For the reference system, bare Ni₆, we calculated two stable octahedron-like isomers in D_3d and C_s symmetry, each with eight unpaired electrons. The latter structure features a broken Ni–Ni bond. We determined only few stable locations of the impurity atoms H, C, or O at the cluster Ni₆. The binding energies of these impurities to Ni₆ increase from 305 kJ/mol for H in a bridge position, to 419 kJ/mol for O in a three-fold position, and 682 kJ/mol for C in a four-fold position. Calculated detachment energies of Ni atoms from Ni₆ and agree well with experiment. Ligand detachment energies of XNi₆ suggest that X = H binds weaker to the cluster than a Ni atom, X = C or O bind stronger. The clusters XNi₆ show some similarities to their smaller congeners XNi₄ and XNi₅, but also notable differences which emphasize the molecule-like individual character of these cluster compounds.