CAJ | 학술논문

用高新程序的B3LYP变换相关函数和全电子基组DGDZVP、TZVP优化了Nin、Ni+n和Ni-n(n=2～8),得到了这些体系的基态几何构型、离化能、电子亲和能以及键能.结果表明；Ni2,Ni3,Ni4,Ni5和Ni6团簇的基态分别是5,7,9,11和13重态.表明:Nj2,Ni3,Nih,Ni5和Ni6团簇中分别有4,6,8,10和12个平行自旋的电子,在每一个Nin团簇中非耦合的电子是最多,这些电子占据不同的轨道,导致每一个Nin团蔟的能量最小,说明在这些Nin团簇中电子平行的效应大于电子耦合的效应,这显然与d电子的离域效应有关,这被称为自旋极化效应,符合宏特规则.Nin、Ni+n和Ni-n (n=2～8)体系的磁矩分别是Nin具有8 μB (n=6～8),Ni-n具有9 μB(n=6～8),Ni-n具有7 μB(n=4～8).
용고신정서적B3LYP변환상관함수화전전자기조DGDZVP、TZVP우화료Nin、Ni+n화Ni-n(n=2～8),득도료저사체계적기태궤하구형、리화능、전자친화능이급건능.결과표명；Ni2,Ni3,Ni4,Ni5화Ni6단족적기태분별시5,7,9,11화13중태.표명:Nj2,Ni3,Nih,Ni5화Ni6단족중분별유4,6,8,10화12개평행자선적전자,재매일개Nin단족중비우합적전자시최다,저사전자점거불동적궤도,도치매일개Nin단족적능량최소,설명재저사Nin단족중전자평행적효응대우전자우합적효응,저현연여d전자적리역효응유관,저피칭위자선겁화효응,부합굉특규칙.Nin、Ni+n화Ni-n (n=2～8)체계적자구분별시Nin구유8 μB (n=6～8),Ni-n구유9 μB(n=6～8),Ni-n구유7 μB(n=4～8).
Density functional theory B3LYP has been performed on the calculations of structure of Ni,,Ni+n and Ni-n (n＝2～8).For both neutral and charged systems,many low-lying states and different multiplicities are studied in order to find the lowest energy structures.DGDZVP all-electron basis sets and TZVP all-electron basis sets are employed.Equilibrium geometries,ionization potentials,electron affinities and binding energies are reported.Our results show that the ground state for the Ni2 cluster is 5-multiple state,Ni3 cluster is 7-multiple state,Ni4 cluster is 9-multiple state,Ni5 cluster is 11-multiple state,Ni6 cluster is 13-multiple state,which indicate a spin polarization effect in the Nin (n≤8) clusters.That is,there are 4 parallel spin electrons in Ni2 cluster,6 parallel spin electrons in Ni3 cluster,8 parallel spin electrons in Ni4cluster,10 parallel spin electrons in Ni5cluster,12 parallel spin electrons in Ni6cluster.The number of non-conjugated electrons in each ground state cluster is the greatest.These electrons occupy different spacious orbitals so that the energy for each Nin (n≤8) cluster is minimized.It can be concluded that the effects of parallel spin in the Nin (n≤8) clusters is larger than the effects of the conjugated dusters,which is obviously related to the effect of electron d delocalization.This condition is spin polarization effect of the Nin(n≤8) clusters.Our study has great significance for GMR (Giant MagnetoResistive).Moreover,by studying the magnetic moments of Nin,Nin+ and Ni-n (n=2～8) clusters,we find that the spin magnetic moments of Nin (n=6～8) are 8μB,the spin magnetic moments of Ni+n (n=6～8) are 9μB and the spin moments of Nin- (n=4～10) are all 7μB.This study is helpful for understanding giant magnetoresistive effect of transition metal clusters.Finally the results show that the stable structures of Ni-n clusters are sometimes different from that of Nin clusters.