| Autor: |
Th.L. Grebner, H. J. Neusser |
| Rok vydání: |
1996 |
| Předmět: |
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| Zdroj: |
International Journal of Mass Spectrometry and Ion Processes. 159:137-152 |
| ISSN: |
0168-1176 |
| Popis: |
Mass analyzed threshold ionization spectroscopy is a versatile technique to measure vibrational spectra of the electronic ground state of polyatomic molecular ions and their complexes with noble gas atoms. The method is based on the separation of promptly produced ions from molecules in high long-lived Rydberg states converging to a selected ionization threshold. After field ionization of the Rydberg states molecular ions in defined vibrational states are produced. We demonstrate for the first time that the so produced threshold ions can be trapped and stored in an electrodynamical ion trap without any background from non-energy-selected prompt ions. As a new result the van der Waals vibrations of the fluorobenzene-Ar complex cation are presented and compared with the respective vibrations in the neutral complex. While the frequency of the stretching mode increases after ionization of the complex, the long axis in-plane bending mode is strongly reduced in frequency. Excitation to vibrational states with more than 543 cm−1 leads to a dissociation of the complex cations and to the appearance of daughter (fluorobenzene) threshold ions. The dissociation energy of the ionic complex E0 ≈ 543 cm−1 and the respective value of the neutral complex is d0 ≈ 321 cm−1. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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