Department of Chemistry and Institute for Molecular Science and Fusion Technology, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Korea.
Phys Chem Chem Phys. 2014 Jan 28;16(4):1590-6. doi: 10.1039/c3cp53521e.
The vibrational spectrum of a pyrimidine cation in the ground electronic state was obtained using vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy. Accurate ionization energy of pyrimidine was determined from the 0-0 band position in the VUV-MATI spectrum and was measured by varying the PFI field to the zero field limit, which is 75,258 ± 7 cm(-1) (9.3308 eV). The spectrum displayed a large number of vibrational peaks, which could be nearly completely assigned through Franck-Condon analysis performed with variations of geometrical parameters at the B3LYP/cc-pVTZ level. Based on the excellent agreement between experimental and calculated results, the definite geometry of the pyrimidine cation in the ground electronic state was determined to be a planar structure with C2v symmetry with a decreased N-N distance in the ring.
采用真空紫外光电离质谱分析（VUV-MATI）光谱法获得了基态嘧啶阳离子的振动光谱。通过将 PFI 场变到零场极限，从 VUV-MATI 光谱的 0-0 带位置确定了嘧啶的精确电离能，该值为 75,258 ± 7 cm(-1)（9.3308 eV）。该光谱显示出大量的振动峰，通过在 B3LYP/cc-pVTZ 水平上改变几何参数进行 Franck-Condon 分析，可几乎完全对其进行归属。基于实验和计算结果之间的良好一致性，确定了基态嘧啶阳离子的确定几何形状为平面结构，具有 C2v 对称性，并且环中的 N-N 距离减小。
