University of Illinois Urbana-Champaign

Group IIB dimers: Spectroscopy of molecular cadmium and gain demonstration in molecular mercury

Tran, Hao Chi

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Description

Title
Group IIB dimers: Spectroscopy of molecular cadmium and gain demonstration in molecular mercury
Author(s)
Tran, Hao Chi
Issue Date
1997
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Physics, Molecular
Language
eng
Abstract
  • The $\rm B\sp1\Sigma\sbsp{u}{+}$ state of $\rm Cd\sb2,$ correlated with $\rm Cd(\sp1S)+Cd(5p\ \sp1P\sb1),$ was studied by laser excitation spectroscopy from the lowest metastable state, $\rm a\sp3\Pi\sb{g}.$ The excitation spectrum of the $\rm B\sp1\Sigma\sbsp{u}{+}\gets a\sp3\Pi\sb{g}$ transition in the 555-725 nm spectral range is presented. Birge-Sponner analysis of the $\rm v\sp{\prime\prime}$ = 0,1 vibrational progressions yielded spectroscopic constants for both the $\rm a\sp3\Pi\sb{g}$ and $\rm B\sp1\Sigma\sbsp{u}{+}$ state potentials. Iterative trial and error simulation of the excitation spectrum established the difference between the internuclear separations $\rm (\Delta R\sb{e})$ of the two states. The ultraviolet emission spectra of the $\rm B\sp1\Sigma\sbsp{u}{+}\to X\sp1\Sigma\sbsp{g}{+}$ (bound$\to$free) transition are presented with comparison to the best calculated spectra to determine the $\rm\Delta R\sb{e}$ between the $\rm B\sp1\Sigma\sbsp{u}{+}$ and $\rm X\sp1\Sigma\sbsp{g}{+}$ states.
  • $\rm GO\sbsp{u}{+}\to XO\sbsp{g}{+}$ bound-free emission spectra of $\rm Hg\sb2$ from several different vibrational levels were analyzed to determine the (1) $\rm\Delta R\sb{e}$ between the $\rm GO\sbsp{u}{+}$ and $\rm XO\sbsp{g}{+}$ states, and (2) the region of internuclear separative over which the mostly dissociative ground state is bound. Photoassociative excitation spectrum is shown for the 265-285 nm spectral region which corroborates the emission data concerning the ground state.
  • Gain on the $\rm GO\sbsp{u}{+}\to XO\sbsp{g}{+}$ transition was observed at ${\sim}227$ nm when a prepared population of $\rm Hg\sb2$ in the metastable $\rm AO\sbsp{g}{+}$ state is pumped with 564.3 nm radiation. This represents an anti-Stokes shift of ${\sim}3.3$ eV of the pump radiation and confirms the reality of a population inversion between the $\rm AO\sbsp{g}{+}$ (storage) state and the dissociative $\rm XO\sbsp{g}{+}$ ground state.
Type of Resource
text
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http://hdl.handle.net/2142/19911
Copyright and License Information
Copyright 1996 Tran, Hao Chi

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