NO在Yn(n=1–12)团簇表面的解离性吸附

采用基于密度泛函理论中的广义梯度近似，在考虑自旋多重度的情况下，对Y_nNO（n=1–12）团簇进行了构型优化，以及稳定性和成键特性分析，结果表明：n=5，7，8，10时，NO吸附使相应的Y_n团簇基态结构发生了明显变化，吸附后，所有尺寸中的N–O键长明显伸长，振动频率减弱，表明NO在Y_n团簇表面发生的是解离性吸附，N–Y，O–Y键的共同作用使Y_nNO团簇具有很大的吸附能；特别是n=3，5，8时，N–O键断裂，吸附能值分别为9.92，9.24，9.82 eV. Y_nNO和Y_n 的二阶能量差分变化趋势表明，NO 吸附对Y_n团簇稳定性和成键特性均产生较大影响. N，O原子sp³轨道杂化时孤对电子的出现导致N–O键断裂，增强了N–Y和O–Y间的成键能力，使Y₃NO，Y₅NO，Y₈NO团簇表现出了很好的稳定性.关键词：团簇NO吸附基态结构稳定性

Dissociative adsorptions of NO on Yn (n=1–12) clusters

The geometry structures, stabilities and chemical bonding properties of the Y_nNO(n=1–12) clusters are studied in the generalized gradient approximation based on the density functional theory with the consideration of spin multiplicities. The results show that NO adsorption changes the basic frameworks of the corresponding Y_n clusters with n=5, 7, 8, 10. The obvious elongation of N–O bond length and the attenuate vibrational frequency indicate that the adsorption of NO on Y_n cluster can be regarded as the dissociative adsorption. The chemical bondings of N–Y and O–Y both simultaneously play an important role in enlarging the adsorption energy of Y_nNO clusters. Specially, Y₃NO, Y₅NO, and Y₈NO have the giant adsorption energies (9.92, 9.24, and 9.82 eV) coupled with the break of the N–O bond. The calculated second-order energy differences suggest that the NO adsorption has influences on the stabilities and bonding properties of Y_n clusters. The appearance of the couple electrons, arising from the sp³ hybridization of N and O atom, not only leads to the fracture of N–O bond, but also enhances the ability to form N–Y bond and O–Y bond, which has important effects on the high stabilities of Y₃NO, Y₅NO, and Y₈NO clusters.
Keywords：clustersNO adsorptionbasic structuresstabilities