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We use the Monte Carlo method to study an antiferromagnetical Ising spin
system on a centred honeycomb lattice, which is composed of two kinds
of 1/2 spin particles A and B. There exist two different bond
energies JA-A and JA-B in this lattice. Our
study is focused on how the ratio of JA-B to JA-A influences the critical behaviour of this system by analysing the physical quantities, such as the energy, the order parameter,
the specific heat, susceptibility, {etc} each as a function of temperature for a given ratio of JA-B to JA-A. Using these results together with the finite-size scaling method,
we obtain a phase diagram for the ratio JA-B / JA-A. This work is helpful for studying the phase transition
problem of crystals composed of compounds. 相似文献
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应用密度泛函理论(DFT)和B3LYP/6-31+G**方法,对金属Cr9团簇与DNA/RNA的碱基的相互作用规律进行了研究. 运用势能面扫描的方法和计算各种复合体的结合能, 得到了Cr9团簇在各碱基的不同的点附近与碱基形成复合体时,其复合体的稳定性大小的分布情况. 发现Cr9团簇通过接近碱基的环上氮原子及氧原子与其结合时,所构成的Cr9团簇-碱基复合体比较稳定. 通过对复合体的前线轨道的分析,找出了各种Cr9团簇-碱基复合体的结合能大小不同的原因.研究结果表明,结合能比较大的Cr9团簇-碱基复合体的最高占有轨道(HOMO)由Cr-d和N-p(或O-p)轨道杂化而成,共价相互作用为团簇与碱基结合的主要因素. 结合能较小的Cr9团簇-碱基复合体的HOMO中没有团簇与碱基的电子云的重叠,范德瓦尔斯力是两者结合的主要因素. 本文的研究对揭示金属铬团簇对生物体影响的规律,以及对探测和监控生物体中铬团簇的都有着要的意义. 相似文献
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