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Title: Visible and near-infrared excitation spectra from the neptunyl ion doped into a uranyl tetrachloride lattice

We present that visible and near-infrared illumination induces 5f-5f and ligand-to-metal charge-transfer (LMCT) transitions of the neptunyl tetrachloride anion in polycrystalline Cs 2U(Np)O 2Cl 4, and results in near-infrared luminescence from the second electronically excited state to the ground state. This photoluminescence is used as a detection method to collect excitation spectra throughout the near-infrared and visible regions. The excitation spectra of LMCT transitions in excitation spectra were identified in previous work. Here the measurement and analysis is extended to include both LMCT and intra-5f transitions. The results manifest variation in structural properties of the neptunium-oxo bond among the low-lying electronic states. Vibronic intensity patterns and energy spacings are used to compare bond lengths and vibrational frequencies in the excited states, confirming significant characteristic differences between those excited by 5f-5f transitions from those due to LMCT transitions. Lastly, results are compared with recently published RASPT2/SO calculations of [NpO 2Cl 4] 2-.
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  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0022-2860
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Molecular Structure
Additional Journal Information:
Journal Volume: 1108; Journal Issue: C; Journal ID: ISSN 0022-2860
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Actinide; Electronic structure; Excitation spectrum; Intra-5f; Ligand-to-metal charge-transfer; Neptunyl
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1396701