Anh chị nào tìm dùm bài báo hoàn chỉnh post lên dùm nhe(khoảng 430kb) trang SpringerLink Dat Tuesday, December 12, 2006
Thanks you very much.
Theoretical Study of Aluminide Clusters Al 13 X, Al 13 ,and Al 13 (X= H, Hal, OH, NH 2 , CH3 , and C6H5) O. P. Charkin a , V. K. Kochnev b , and N. M. Klimenko b a Institute of Problems of Chemical Physics, Russian Academy of ciences,Chernogolovka,
Tóm tắt
The structural, electronic, energy, and vibrational characteristics of the Al 13 and Al 13 clusters,with an aluminum-centered ( Al c ) icosahedral cage Al 13 and with one or two outer-sphere ligands X = H, F, Cl, Br,OH, NH2 , CH3 , C6H5 , have been calculated within the B3LYP approximation of the density functional theoryusing the 6-31G* and 6-311+G* basis sets. In all Al 13 radicals, the unpaired electron is localized at the cageatom Al* located opposite the Al–X bond. This Al* atom is the most favorable site for attaching the secondX ligand of any nature (trans-addition rule). According to the previously suggested molecular model of the valencestate of the [] “superatom,” the calculated energies D 1 ( − X) of addition of the first liand to the anion are about 1 eV lower than the corresponding energies of addition of the second ligand D 2 (ï − X) . Thestructure of the Al13 cage depends on the nature of the nature of the substituent X and can radically change in goingfrom anions to their neutral congeners. In the lowest-lying Al 13 ï isomer with electronegative substituents X (Hal,OH, NH 2 , CH 3 , etc.), the aluminum cage has a marquee structure ( 1 , symmetry C s ) with a hexagonal base and apentagonal “roof.” For Al 13 ï analogues with electropositive ligands X (Al, Li, Na), a tridentate isomer ( T, C3 v )with the X substituent coordinated to a face of the Al 13 icosahedron is preferable. In the case of moderately elec-tronegative X ligands (of the H type), the marquee ( 1 ) and icosahedral ( T ) isomers are close in energy. The stretch-ing vibration frequencies of isomers 1 and T differ significantly in magnitude and intensity so that vibrational spectroscopy methods can be especially applicable to their experimental identification DOI: 10.1134/S003602360612014XX–
thay đổi nội dung bởi: hoangkhacson, ngày 02-02-2010 lúc 02:31 PM.
|