Tono Kensuke, Terasaki Akira, Ohta Toshiaki, Kondow Tamotsu
Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
J Chem Phys. 2005 Nov 1;123(17):174314. doi: 10.1063/1.2062265.
The binding energies of manganese cluster ions Mn(N)+ (N = 5-7) were determined by the photodissociation experiments in the near-infrared and visible-photon-energy ranges. The bond dissociation energies of Mn(N)+, D0(Mn(N-1)+...Mn), were obtained to be 1.70+/-0.08, 1.04+/-0.10, and 1.46+/-0.11 eV, respectively, for N = 5, 6, and 7 from the threshold energies for the two-atom loss processes and the bond dissociation energies of Mn3(+) and Mn4(+) reported previously [A. Terasaki et al., J. Chem. Phys. 117, 7520 (2002)]. Correspondingly, binding energies per atom are obtained to be 0.99+/-0.03, 1.00+/-0.03, and 1.06+/-0.03 eV/at. for N = 5, 6, and 7, respectively. A gradual increase in the binding energy from N = 2 to N = 7 shows an increasing contribution of nonbonding 3d orbitals to the bonding via weak hybridization with valence 4s orbitals as the cluster size increases. These binding energies per atom are still much smaller than the bulk cohesive energy of manganese (2.92 eV/at.), and this finding indicates exceptionally weak metal-metal bonds in this size range.
通过在近红外和可见光光子能量范围内的光解离实验，测定了锰簇离子Mn(N)+（N = 5 - 7）的结合能。根据双原子损失过程的阈值能量以及先前报道的Mn3(+)和Mn4(+)的键解离能[A. Terasaki等人，《化学物理杂志》117, 7520 (2002)]，对于N = 5、6和7，Mn(N)+的键解离能D0(Mn(N - 1)+...Mn)分别为1.70±0.08、1.04±0.10和1.46±0.11 eV。相应地，对于N = 5、6和7，每个原子的结合能分别为0.99±0.03、1.00±0.03和1.06±0.03 eV/原子。随着簇尺寸的增加，从N = 2到N = 7结合能逐渐增加，这表明随着簇尺寸的增加，非键合3d轨道通过与价4s轨道的弱杂化对键合的贡献增加。这些每个原子的结合能仍然远小于锰的体凝聚能（2.92 eV/原子），这一发现表明在这个尺寸范围内金属 - 金属键异常弱。
