摘要
用原子交叠和电子离域-分子轨道(ASED-MO)方法研究N_2在Cr(110)面的化学吸附过程。结果表明,N_2平行吸附于Cr(110)面的四度空位,N-N轴平行于[110]方向,与传统的σ施予和π弱反键作用不同,N_2在Cr(110)面平行吸附时,不仅3σ_g而且1π_μ分别向衬底施予0.97和0.54个电子,同时1π_g的反向键合增加到1.83个电子,这导致平行吸附比垂直吸附具有更低的能量,它是一种强化学吸附,另外,平行吸附的N_2分子键长伸长了17%,键级下降到1以下,其势离解垒仅为0.15eV,上述计算结果与有关实验符合得很好。
An ASED-MO method has been applied to investigate the N2 chemisorption on Cr(110) surface. The results show that N2 chemisorbs parallelly on the 4-fold site with N-N axis parallel to [110] direction. Different from the tranditional σ-donation and π weak backbonding concepts, the N2 chemisorption on Cr(110) has both the 3 σg and 1 πμ donations of 0.97 and 0.54 electrons. At the same time, the backbonding to the 1 πg orbital increases to 1.83 electrons. Both these factors make the lying-down orientation being favored over the upright orientation. Furthermore, the N-N bond length strenches 17%, the N-N bond order decreases to below 1, and the dissociation barrier is only about 0.15 eV. All the above calculation results are in good agreement with relevant experiments.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1992年第2期295-301,共7页
Acta Physica Sinica
基金
国家自然科学基金
