M_n(SiO_2)_3(M=Fe,Co,Ni;n=1-3)团簇的几何结构、光电性质及磁性

Structural,Photoelectric and Magnetic Properties of M_n( SiO_2)_3( M =Fe,Co,Ni; n =1-3) Clusters

基于密度泛函理论中的广义梯度近似系统研究Mn(SiO2)3(M=Fe,Co,Ni;n=1-3)团簇的几何结构、光电性质和磁学性质.结果表明:Fe,Co原子相对于Ni原子更易于在(SiO2)3团簇上聚集;通过分析团簇的分裂途径及其产物,发现稳定性较好的氧化硅是一种很好的用于负载过渡金属"岛膜"的载体材料;Mn(SiO2)3团簇的能隙恰好位于近红外光谱范围内.通过磁性分析发现,该复合团簇的磁矩主要局域在过渡金属原子周围,而且,Fe2(SiO2)3和Co3(SiO2)3具有相对较大的磁矩,这主要源于过渡金属原子的d轨道间相互耦合.能隙和磁性两方面性质进一步肯定了二氧化硅磁性复合材料在医学界被用作光动力靶向治疗的可观前景.

Equilibrium geometries,electronic and magnetic properties of Mn( SiO2)3( M = Fe,Co,Ni; n = 1-3) clusters are systematically studied employing density functional theory with a generalized gradient approximation. It shows that Fe and Co atoms are easier to congregate on( SiO2)3cluster than Ni atoms. It is found that stabler silica is an excellent matrix materials to carry islands of transition-metals. Energy gaps of Mn( SiO2)3( M = Fe,Co,Ni; n =1-3) clusters lie in near infrared radiation region. In analysis of magnetism,it is found that their magnetic moments are mainly located on transition-metal atoms. Fe2( SiO2)3and Co3( SiO2)3have greater magnetic moments,owing to coupling between d orbits of transition-metal atoms. Energy gap and magnetic property affirm a considerable foreground of magnetic-mulriple silica used for photodynamic target therapy in medical stage.