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arXiv · 1404.2180

The $A^{1}Σ^{+}_{u}$ + (1)$^1Π_u$ system of Mg$_2$

Horst Knöckel·Steffen Rühmann·Eberhard Tiemann
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Abstract

The $A^1Σ^+_u$ - $X^1Σ^+_g$ UV spectrum of Mg$_2$ has been investigated with high resolution employing Fourier-transform spectroscopy and laser excitation. Computer simulation and fit of line positions to the overlapping structures in the spectra yield precise transition frequencies. Starting with the well characterized ground state $X^1Σ^+_g$ from former work we derived excited energy levels and report on the evaluation of the $A^1Σ^+_u$ excited state, which is found to interact with another electronic state, which we identify as the lower part of the (1)$^1Π_u$ state. A coupled channels fit to the level energies of the upper state yields a reliable potential energy curve for the $A^1Σ^+_u$ for the range of vibrational levels 1 $\le$ $v'$ $\le$ 46. A potential energy curve for the (1)$^1Π_u$ state is proposed, but the (1)$^1Π_u$ state is only characterized by its coupling to the A state, and no direct transition to a level of the (1)$^1Π_u$ could be uniquely identified due to the overlapping spectral structures.

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Horst Knöckel, Steffen Rühmann, Eberhard Tiemann. 2014-04-14. The $A^{1}Σ^{+}_{u}$ + (1)$^1Π_u$ system of Mg$_2$. https://doi.org/10.1140/epjd%2Fe2014-50289-9

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