Electronic transitions and vibronic coupling in neptunyl compounds
Guokui Liu1, Shuao Wang, Thomas E Albrecht-Schmitt
1Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States. gkliu@anl.gov
The Journal of Physical Chemistry. A
|July 13, 2012
Summary
Neptunyl (NpO(2)(2+)) electronic transitions show distinct charge transfer (CT) and intra-5f behaviors. CT vibronic coupling in neptunyl mirrors uranyl analogues, differing from f-f transitions.
Area of Science:
- Inorganic Chemistry
- Spectroscopy
- Quantum Chemistry
Background:
- Neptunyl (NpO(2)(2+)) ions exhibit complex electronic transitions.
- Understanding these transitions is crucial for predicting neptunyl behavior in various chemical environments.
- Photophysical properties, particularly vibronic coupling, vary significantly between different electronic transition types.
Purpose of the Study:
- To characterize the low-lying electronic transitions of the neptunyl ion.
- To compare the photophysical properties, especially vibronic coupling, of charge transfer (CT) and intra-5f transitions.
- To analyze the absorption spectra of neptunyl in different compounds using an empirical model.
Main Methods:
- Characterization of electronic transitions as charge transfer (CT) or intra-5f.
- Simulation of neptunyl absorption (excitation) spectra using an empirical model for CT vibronic transitions.
- Analysis of vibronic coupling strength and vibrational mode frequencies.
Main Results:
- CT vibronic coupling in neptunyl exhibits characteristics similar to uranyl analogues.
- The spectral profiles of CT transitions are consistent across different neptunyl bonding interactions (chloride- and oxide-neptunium).
- Vibronic coupling to CT transitions differs markedly from f-f transitions within the same neptunyl compound.
Conclusions:
- The study provides insights into the distinct photophysical properties of neptunyl electronic transitions.
- The findings confirm the applicability of the empirical model for analyzing neptunyl CT vibronic transitions.
- Detailed electronic energy levels and vibronic parameters were evaluated for neptunyl compounds.
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