C20分子与C20^±离子的电子及光谱特性分析比较

Analytic Comparison of Electron and Spectrum Characteristics for the C20 Molecule and the C20^± Ion

利用Gaussion98对C20分子及C2±0离子进行了结构优化、频率计算,得到了没有虚频的稳定结构。在此基础上对C20分子及C20±离子的电子结构和振动光谱进行了比较分析。自然键轨道理论(NBO)分析表明:三者都具有离域特性,C20分子及C20-离子的电子都向部分原子转移,它们的共价键是带有部分离子性质的共价键。对三者的光谱计算显示C20+离子几乎没有红外吸收特性,而喇曼光谱较容易将C20分子和C20±离子分辨开来。红外光谱可以将C20-离子与C20+离子区分开。

The structure optimization and the frequency calculation were completed for the C20 molecule and the C20^± ion by Gaussion98 and the stable structure without the imaginary frequency was obtained. Then the electronic structures and the vibration spectra of the C20 molecule and the C20^± ion were compared and analyzed. The NBO analysis shows that the three have all delocalization characteristics. The electrons of the C20 molecule and the C20^- ion transfer to a few atoms, and their covalent bonds are something like the covalent bond with some ion characters. The vibration spectra show that the C20^± ion has almost no infrared spectrum. The Raman spectrum can easily distinguish the C20 molecule from C20^± ion, and the infrared spectrum can distinguish the C20^- ion from the C20^± ion.