Analytical and ab initio studies of effective exchange interactions, polyradical character, unpaired electron density, and information entropy in radical clusters (R)N:: Allyl radical cluster (N=2-10) and hydrogen radical cluster (N=50)
Analytical and ab initio studies of effective exchange interactions, polyradical character, unpaired electron density, and information entropy in radical clusters (R)N:: Allyl radical cluster (N=2-10) and hydrogen radical cluster (N=50)
复制标题
DOI：
10.1002/qua.979
复制
发表时间：
2002-10-05
影响因子：
2.2
通讯作者：
Fujita, H
中科院分区：
文献类型：
--
作者：
Yamaguchi, K;Kawakami, T;Fujita, H
在Hubbard模型的基础上，导出了烯丙基自由基二聚体和三聚体的总能量、有效交换积分、多自由基特征、自旋密度、未配对电子密度和信息熵的解析表达式，以阐明几种破缺对称和适应对称的分子磁学方法之间的相互关系。对烯丙基自由基二聚体到十聚体的从头算和杂化密度泛函理论（DFT）进行了计算，以证实分析研究揭示的特征。采用从头算混合DFT方法研究了具有50个自由基位的介观氢自由基簇，以阐明上述量随原子间距离变化的泛函行为。为了达到这个目的，用这些方法描绘了团簇的最低和最高自旋态的势曲线。本计算结果的意义讨论了尺寸一致的自旋投影和尺寸对介观自由基团簇中有效交换相互作用的影响。(C) 2002 Wiley期刊有限公司
Analytical expressions of total energies, effective exchange integrals, polyradical character, spin density, unpaired electron density, and information entropy are derived for allyl radical dimers and trimers on the basis of the Hubbard model in order to elucidate interrelationships among several broken-symmetry and symmetry-adapted approaches to molecular magnetism. Ab initio unrestricted Hartree-Fock and hybrid density functional theory (DFT) calculations of allyl radical dimers to decamers are also carried out for confirmation of characteristics revealed by the analytical investigations. A mesoscopic hydrogen radical cluster with 50 radical sites is studied by the ab initio hybrid DFT methods to elucidate functional behaviors of the above quantities with change of interatomic distance. The potential curves for the lowest and highest spin states of the cluster by these methods are depicted for the purpose. Implications of the present computational results are discussed in relation to size-consistent spin projection and size effects on effective exchange interactions in mesoscopic radical clusters. (C) 2002 Wiley Periodicals, Inc.