Molecular Beam Laser Spectroscopy of ReF: Rotational and Hyperfine Analyses of Two Bands near 557 nm
✍ Scribed by O. Launila; A.M. James; B. Simard
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 521 KB
- Volume
- 164
- Category
- Article
- ISSN
- 0022-2852
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✦ Synopsis
An extensive survey of the electronic spectrum of the ReF molecule has been carried out in the region 15 150-29 (600 \mathrm{~cm}^{-1}) using laser-induced fluorescence spectroscopy. The ReF molecules were produced by chemical reaction in a laser-generated plasma and cooled by supersonic expansion. Both isotopomers ({ }^{185} \mathrm{Re}{ }^{19} \mathrm{~F}(37.1 %)) and ({ }^{187} \mathrm{Re}^{19} \mathrm{~F}(62.9 %)) were studied. The observed bands are interpreted as transitions involving two different lower (\Omega=0) states and a number of different excited electronic states. Using a ring dye laser, two of the bands were recorded at (100-) (\mathrm{MHz}) resolution, which was sufficient to resolve hyperfine structure. The analysis of these bands shows that both arise from (\Omega=0 \leftarrow \Omega=0) transitions involving a common lower state (a\left(v^{\prime \prime}\right)) and two strongly interacting upper states (b\left(v^{\prime}\right)) and (c\left(v^{\prime}=2\right)), located at, respectively, 17931 and (17966 \mathrm{~cm}^{-1}) above (a). The (b\left(v^{\prime}\right)) state exhibits an avoided crossing with an unidentified state. Dispersed fluorescence studies reveal the presence of two low-lying states located at 2750 and (4240 \mathrm{~cm}^{-1}) above the (a) state. The energy difference between the two low-lying (\Omega=0) states is not known; neither is it known which one is the ground state. The observed hyperfine structure is attributed to electric quadrupole effects. cc 1994 Academic Press. Inc.