EXPERIMENTAL DETERMINATION OF THE POTENTIAL CURVE FOR THE STATE RADIATING THE ARGON VACUUM ULTRAVIOLET CONTINUA
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Date
1972
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Ohio State University
Abstract
The argon first and second continua have been shown to arise from molecular states produced from the $^{3}P_{2}$ metastable atomic $state.^{1}$ In the present work the oscillatory first continuum has been analyzed by the method of $Smith^{2}$ to extract the upper state potential curve. The relevant molecular state is either $^{3}\Sigma_{u}^{+}(1_{u})$ correlating to ($^{3}P_{2}+^{1}S_{0}$) or $^{1}\Sigma_{u}^{+}(o_{u}^{+})$ correlating to ($^{3}P_{1}+^{1}S_{0}$); if the former its dissociation energy is $$0.6\ eV <D_{e} \approx 0.8 \ eV < 0.9 \ eV;$$ if the latter, $$0.675\ eV <D_{e} \approx 0.875\ eV < 0.975\ eV.$$ The equilibrium separation of the radiating state is $$2.15\ \hbox{\AA} < R_{e} \approx 2.22 \ \hbox{\AA} \approx 2.4 \ \hbox{\AA};$$ its vibrational constant is $315 cm^{-1} < \omega_{e}\approx 410$ $cm^{-1} < 440$ $cm^{-1}$. Using the potential so obtained, the intensity distribution in the second continuum was calculated assuming radiation from a thermal distribution of the lowest vibrational levels in the same molecular state that radiates the first continuum; the results were in excellent accord with experiment. It should be noted that the potential parameters obtained here are rather different from those for $Ar_{2}^{+}$.
Description
$^{1}$ R. Michaelson and A.L. Smith, Chem. Phys. Letters 6, 1 (1970). $^{2}$ A.L. Smith, J. Chem. Phys., 49, 4813, 4817, (1968).""
Author Institution: Department of Chemistry, University of Prince Edward Island; Department of Chemistry, Yale University
Author Institution: Department of Chemistry, University of Prince Edward Island; Department of Chemistry, Yale University