Fourier Transform Emission Spectroscopy of theA2Π–X2Σ+Transition of BeD

✍ Scribed by C. Focsa; P.F. Bernath; R. Mitzner; R. Colin

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 476 KB
• Volume: 192
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1998.7700

✦ Synopsis

The A 2 ⌸-X 2 ⌺ ϩ ⌬v ϭ 0 sequence of BeD was observed in the 19 500 -20 800 cm Ϫ1 spectral region using a Fourier transform spectrometer. The emission spectrum was excited in a Be hollow cathode discharge lamp with a He/D 2 gas mixture. The observed lines were assigned to the 0 -0 to 6 -6 bands. The ⌬v ϭ Ϫ1 sequence was too weak to be seen in our Fourier transform spectra. We therefore used a previously recorded but unpublished arc emission spectrum to identify the 0 -1 to 5-6 ⌬v ϭ Ϫ1 bands. Consequently, all of the diagonal bands could be linked together and the vibrational intervals determined. The ⌬v ϭ 0 and ⌬v ϭ Ϫ1 data were fitted together in a global fit and effective constants derived. Using the information available from the study of the C 2 ⌺ ϩ -X 2 ⌺ ϩ system [R. Colin, C. Dre `ze, and M. Steinhauer, Can. J. Phys. 61, 641 (1983)], the v ϭ 8 -12 vibrational levels of the ground state were added in a Dunham fit. A set of Dunham Y constants was determined for the X 2 ⌺ ϩ state along with traditional equilibrium parameters for the A 2 ⌸ excited state. The equilibrium bond lengths were found to be 1.341742(5) Å for the ground state and 1.33309(4) Å for the excited state. A reanalysis of the previously published A 2 ⌸-X 2 ⌺ ϩ 0-0 to 3-3 ⌬v ϭ 0 bands of BeT [D. De Greef and R. Colin, J. Mol. Spectrosc. 53, 455-465 (1974)] was also performed.