Shape resonance spectra of uracil, 5-fluorouracil, and 5-chlorouracil
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-990 Curitiba, Paraná (Brazil)
We report on the shape resonance spectra of uracil, 5-fluorouracil, and 5-chlorouracil, as obtained from fixed-nuclei elastic scattering calculations performed with the Schwinger multichannel method with pseudopotentials. Our results are in good agreement with the available electron transmission spectroscopy data, and support the existence of three π* resonances in uracil and 5-fluorouracil. As expected, the anion states are more stable in the substituted molecules than in uracil. Since the stabilization is stronger in 5-chlorouracil, the lowest π* resonance in this system becomes a bound anion state. The present results also support the existence of a low-lying σ{sub CCl{sup *}} shape resonance in 5-chlorouracil. Exploratory calculations performed at selected C–Cl bond lengths suggest that the σ{sub CCl{sup *}} resonance could couple to the two lowest π* states, giving rise to a very rich dissociation dynamics. These facts would be compatible with the complex branching of the dissociative electron attachment cross sections, even though we cannot discuss any details of the vibration dynamics based only on the present fixed-nuclei results.
- OSTI ID:
- 22253588
- Journal Information:
- Journal of Chemical Physics, Vol. 140, Issue 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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