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Title: Evaluation of the exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −}

Abstract

The exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −} has been re-evaluated through the combination of several experimental methods. The thermal reactivity (300–650 K) of Sm{sup +} and SmO{sup +} with a range of species measured using a selected ion flow tube-mass spectrometer apparatus is reported and provides limits for the bond strength of SmO{sup +}, 5.661 eV ≤ D{sub 0}(Sm{sup +}-O) ≤ 6.500 eV. A more precise value is measured to be 5.72{sub 5} ± 0.07 eV, bracketed by the observed reactivity of Sm{sup +} and SmO{sup +} with several species using a guided ion beam tandem mass spectrometer (GIBMS). Combined with the established Sm ionization energy (IE), this value indicates an exothermicity of the title reaction of 0.08 ± 0.07 eV, ∼0.2 eV smaller than previous determinations. In addition, the ionization energy of SmO has been measured by resonantly enhanced two-photon ionization and pulsed-field ionization zero kinetic energy photoelectron spectroscopy to be 5.7427 ± 0.0006 eV, significantly higher than the literature value. Combined with literature bond energies of SmO, this value indicates an exothermicity of the title reaction of 0.14 ± 0.17 eV, independent from and in agreement with the GIBMS resultmore » presented here. The evaluated thermochemistry also suggests that D{sub 0}(SmO) = 5.83 ± 0.07 eV, consistent with but more precise than the literature values. Implications of these results for interpretation of chemical release experiments in the thermosphere are discussed.« less

Authors:
; ; ; ; ; ;  [1]
  1. Department of Chemistry, University of North Florida, Jacksonville, Florida 32224 (United States)
Publication Date:
OSTI Identifier:
22415611
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 142; Journal Issue: 13; Other Information: (c) 2015 AIP Publishing LLC; 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; BINDING ENERGY; CHEMICAL BONDS; EV RANGE; EVALUATION; ION BEAMS; KINETIC ENERGY; MASS SPECTROSCOPY; MOLECULAR IONS; PHOTOELECTRON SPECTROSCOPY; PHOTOIONIZATION; REACTIVITY; SAMARIUM; SAMARIUM OXIDES; THERMOSPHERE

Citation Formats

Cox, Richard M, Kim, JungSoo, Armentrout, P. B., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, Bartlett, Joshua, VanGundy, Robert A., Heaven, Michael C., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, Ard, Shaun G., Shuman, Nicholas S., Viggiano, Albert A., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, and Melko, Joshua J. Evaluation of the exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −}. United States: N. p., 2015. Web. doi:10.1063/1.4916396.
Cox, Richard M, Kim, JungSoo, Armentrout, P. B., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, Bartlett, Joshua, VanGundy, Robert A., Heaven, Michael C., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, Ard, Shaun G., Shuman, Nicholas S., Viggiano, Albert A., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, & Melko, Joshua J. Evaluation of the exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −}. United States. doi:10.1063/1.4916396.
Cox, Richard M, Kim, JungSoo, Armentrout, P. B., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, Bartlett, Joshua, VanGundy, Robert A., Heaven, Michael C., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, Ard, Shaun G., Shuman, Nicholas S., Viggiano, Albert A., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil, and Melko, Joshua J. Tue . "Evaluation of the exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −}". United States. doi:10.1063/1.4916396.
@article{osti_22415611,
title = {Evaluation of the exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −}},
author = {Cox, Richard M and Kim, JungSoo and Armentrout, P. B., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil and Bartlett, Joshua and VanGundy, Robert A. and Heaven, Michael C., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil and Ard, Shaun G. and Shuman, Nicholas S. and Viggiano, Albert A., E-mail: armentrout@chem.utah.edu, E-mail: mheaven@emory.edu, E-mail: albert.viggiano@us.af.mil and Melko, Joshua J.},
abstractNote = {The exothermicity of the chemi-ionization reaction Sm + O → SmO{sup +} + e{sup −} has been re-evaluated through the combination of several experimental methods. The thermal reactivity (300–650 K) of Sm{sup +} and SmO{sup +} with a range of species measured using a selected ion flow tube-mass spectrometer apparatus is reported and provides limits for the bond strength of SmO{sup +}, 5.661 eV ≤ D{sub 0}(Sm{sup +}-O) ≤ 6.500 eV. A more precise value is measured to be 5.72{sub 5} ± 0.07 eV, bracketed by the observed reactivity of Sm{sup +} and SmO{sup +} with several species using a guided ion beam tandem mass spectrometer (GIBMS). Combined with the established Sm ionization energy (IE), this value indicates an exothermicity of the title reaction of 0.08 ± 0.07 eV, ∼0.2 eV smaller than previous determinations. In addition, the ionization energy of SmO has been measured by resonantly enhanced two-photon ionization and pulsed-field ionization zero kinetic energy photoelectron spectroscopy to be 5.7427 ± 0.0006 eV, significantly higher than the literature value. Combined with literature bond energies of SmO, this value indicates an exothermicity of the title reaction of 0.14 ± 0.17 eV, independent from and in agreement with the GIBMS result presented here. The evaluated thermochemistry also suggests that D{sub 0}(SmO) = 5.83 ± 0.07 eV, consistent with but more precise than the literature values. Implications of these results for interpretation of chemical release experiments in the thermosphere are discussed.},
doi = {10.1063/1.4916396},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 13,
volume = 142,
place = {United States},
year = {2015},
month = {4}
}