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High-Resolution Laser Spectroscopy of YbCl: The A(2)Pi-X(2)Sigma(+) Transition
1Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, B3H 4J3, Canada
Journal of Molecular Spectroscopy
|March 10, 2000
Summary
This study presents the first rotational analysis of the A(2)Pi-X(2)Sigma(+) transition in ytterbium chloride isotopomers. High-accuracy laser spectroscopy determined molecular parameters for the A(2)Pi and X(2)Sigma(+) states.
Area of Science:
- Molecular Spectroscopy
- Quantum Chemistry
- Atomic Physics
Background:
- The electronic structure and dynamics of diatomic molecules are fundamental to understanding chemical bonding and reactivity.
- Ytterbium chloride (YbCl) is a molecule with potential applications in areas such as laser cooling and precision measurements.
- Previous spectroscopic studies of YbCl have been limited, necessitating further investigation into its excited and ground states.
Purpose of the Study:
- To perform the first-ever rotational analysis of the A(2)Pi-X(2)Sigma(+) electronic transition in (174)YbCl and (172)YbCl.
- To accurately determine the molecular parameters for the A(2)Pi and X(2)Sigma(+) states of these isotopomers.
- To investigate the interaction between the A(2)Pi and X(2)Sigma(+) states and its effect on spin-rotation splitting.
Main Methods:
- Doppler-limited laser excitation spectroscopy with selective fluorescence detection.
- High-resolution recording of the 0-0 and 1-0 vibrational bands.
- Resolved fluorescence spectroscopy for recording vibrational progressions (0-1, 0-2, 0-3 bands).
- Precise measurement and assignment of over 1300 spectral lines per isotopomer.
- Least-squares fitting of molecular parameters to experimental data.
Main Results:
- Accurate molecular parameters determined for the A(2)Pi state (A(e) = 1491.494(2) cm(-1), R(e) = 2.4433(1) Å) and X(2)Sigma(+) state (R(e) = 2.4883(2) Å, gamma(e) = 4.59(2) x 10(-3) cm(-1)).
- Unequivocal assignment of rotational quantum numbers (N) facilitated by resolved fluorescence.
- Over 1300 line positions measured and assigned for each of the two isotopomers ((174)YbCl and (172)YbCl).
- Measurement accuracy achieved at approximately 0.0035 cm(-1).
Conclusions:
- The A(2)Pi-X(2)Sigma(+) transition in YbCl has been successfully rotationally analyzed for the first time.
- The determined molecular parameters provide crucial data for theoretical modeling and understanding the electronic structure of YbCl.
- The interaction between the A(2)Pi and X(2)Sigma(+) states is identified as the primary cause of spin-rotation splitting in the ground state.
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