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Title: Na{sup -} photolysis in THF: Charge transfer to solvent studied from the donors perspective in <10 fs detail

Abstract

Two and three pulse photolysis experiments on terahydrofuran (THF) solutions of Na{sup -}, utilizing hyperspectral probing, are described. The objective is to probe the extent and duration of energetic correlations between the primary charge transfer to solvent (CTTS) fragments which are an e{sup -} and Na{sup 0}. The latter is characterized by an intense visible absorption spectrum with fine structure reflecting the atom's immediate solvent environment. Pump-probe experiments with {approx}6 fs pulses show that for the majority of irradiated ions, the electron ejection and production of unperturbed Na{sup 0} is effectively over in {approx}15 fs, with no precursors. Three pulse experiments further demonstrate this to be true for nearly all ions irradiated at 3 eV. Thus, the 400 nm data provide a detailed spectral record of the formation and subsequent solvation and polarization of neutral sodium bubbles in THF. Measures are presented for parametrizing the ensuing spectral evolution. In contrast, exciting at 1.5 eV, the red edge of the CTTS band leads to charge transfer with less than unity quantum efficiency. The complementary fraction of absorbing ions is photostable at 800 nm, presumably due to preferential solvent stabilization. Prompt secondary irradiation at 2 {mu}m can complete ionization of that populationmore » leading to additional generation of Na{sup 0} but exhibiting much more pronounced spectral structure. Thus, at low photon energies, a short lived correlated and bound electronic excited state is produced with significant yield. These results are discussed in terms of classical models for CTTS spectra, as well as more recent simulations and experiments concerning CTTS in this and other related systems.« less

Authors:
;  [1]
  1. Institute of Chemistry and the Farkas Center for Light Induced Processes, Hebrew University, Jerusalem 91904 (Israel)
Publication Date:
OSTI Identifier:
21106210
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 129; Journal Issue: 4; Other Information: DOI: 10.1063/1.2946701; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ABSORPTION SPECTRA; CHARGE EXCHANGE; EV RANGE 01-10; EXCITED STATES; FINE STRUCTURE; IONIZATION; IRRADIATION; PHOTOLYSIS; POLARIZATION; PROBES; PULSES; QUANTUM EFFICIENCY; SIMULATION; SODIUM IONS; SOLVATION; SOLVENTS; STABILIZATION; TETRAHYDROFURAN

Citation Formats

Shoshanim, Ofir, and Ruhman, Sanford. Na{sup -} photolysis in THF: Charge transfer to solvent studied from the donors perspective in <10 fs detail. United States: N. p., 2008. Web. doi:10.1063/1.2946701.
Shoshanim, Ofir, & Ruhman, Sanford. Na{sup -} photolysis in THF: Charge transfer to solvent studied from the donors perspective in <10 fs detail. United States. https://doi.org/10.1063/1.2946701
Shoshanim, Ofir, and Ruhman, Sanford. Mon . "Na{sup -} photolysis in THF: Charge transfer to solvent studied from the donors perspective in <10 fs detail". United States. https://doi.org/10.1063/1.2946701.
@article{osti_21106210,
title = {Na{sup -} photolysis in THF: Charge transfer to solvent studied from the donors perspective in <10 fs detail},
author = {Shoshanim, Ofir and Ruhman, Sanford},
abstractNote = {Two and three pulse photolysis experiments on terahydrofuran (THF) solutions of Na{sup -}, utilizing hyperspectral probing, are described. The objective is to probe the extent and duration of energetic correlations between the primary charge transfer to solvent (CTTS) fragments which are an e{sup -} and Na{sup 0}. The latter is characterized by an intense visible absorption spectrum with fine structure reflecting the atom's immediate solvent environment. Pump-probe experiments with {approx}6 fs pulses show that for the majority of irradiated ions, the electron ejection and production of unperturbed Na{sup 0} is effectively over in {approx}15 fs, with no precursors. Three pulse experiments further demonstrate this to be true for nearly all ions irradiated at 3 eV. Thus, the 400 nm data provide a detailed spectral record of the formation and subsequent solvation and polarization of neutral sodium bubbles in THF. Measures are presented for parametrizing the ensuing spectral evolution. In contrast, exciting at 1.5 eV, the red edge of the CTTS band leads to charge transfer with less than unity quantum efficiency. The complementary fraction of absorbing ions is photostable at 800 nm, presumably due to preferential solvent stabilization. Prompt secondary irradiation at 2 {mu}m can complete ionization of that population leading to additional generation of Na{sup 0} but exhibiting much more pronounced spectral structure. Thus, at low photon energies, a short lived correlated and bound electronic excited state is produced with significant yield. These results are discussed in terms of classical models for CTTS spectra, as well as more recent simulations and experiments concerning CTTS in this and other related systems.},
doi = {10.1063/1.2946701},
url = {https://www.osti.gov/biblio/21106210}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 4,
volume = 129,
place = {United States},
year = {2008},
month = {7}
}