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Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet VUV Synchrotron Radiation
Published on: October 30, 2012
Determination of precise pyrimidine cationic structure by vacuum ultraviolet mass-analyzed threshold ionization
Jae Han Kim1, Ji Hye Lee, Hyonseok Hwang
1Department of Chemistry and Institute for Molecular Science and Fusion Technology, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Korea. chkwon@kangwon.ac.kr hlkim@kangwon.ac.kr.
Abstract:
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.
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