Ab initio calculation of hyperfine structure and Raman spectra of binary alkali metal silicates

作者：Zeng Hao; You Jing lin^*; Chen Hui; Jiang Guo chang

来源：Spectroscopy and Spectral Analysis, 2007, 27(6): 1143-1147.

• Raman spectra
• silicate
• hyperfine structure
• Ab initio calculation
• stress index of tetrahedron

Ab initio calculation method of quantum chemistry was used to optimize several typical binary alkali metals silicates model clusters under restricted Hartree-Fock method with 6-31G(d) basis sets. The symmetric stretching vibrational frequency of non-bridging oxygen in the high frequency range, its Raman optical activity (ROA) and the influence of different cations of those model clusters were also calculated and evaluated with the concept of hyperfine micro-structure. It was shown that the symmetric stretching vibrational frequency of non-bridging oxygen in the high frequency range is related closely to the environmental hyperfine micro-structure, and ROA enhancement of Q(3) species occurs as Q(4) species is its nearest neighbor. It can be inferred that the Raman scattering properties of silicates might be predominantly determined by hyperfine micro-structure instead of crude SiO4 tetrahedron as primary micro-structure. It was found that large cation can enhance ROA of the symmetric stretching vibration of non-bridging oxygen by charge transfer mechanism, while ROA weakening effect can be expected on small model clusters due to the excessive charge transfer.

• 出版日期2007-6
• 单位上海大学