Fourier Transform Spectroscopy of the A′1Π–X1Σ+ System of CaO

✍ Scribed by C. Focsa; A. Poclet; B. Pinchemel; R.J. Le Roy; P.F. Bernath

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 190 KB
• Volume: 203
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2000.8187

✦ Synopsis

The AЈ 1 ⌸-X 1 ⌺ ϩ near-infrared system of CaO was observed for the first time at high resolution using a Fourier transform spectrometer. The AЈ 1 ⌸-X 1 ⌺ ϩ chemiluminescence was excited in a Ca ϩ N 2 O flame produced in a Broida-type oven. More than 3000 rotational lines, classified into 19 bands involving the AЈ 1 ⌸ 0 Յ vЈ Յ 3 and the X 1 ⌺ ϩ 1 Յ vЉ Յ 7 vibrational levels were measured in the 4000 -10 000 cm Ϫ1 region with a precision of 0.005 cm Ϫ1 . The X 1 ⌺ ϩ (v ϭ 0, 1) millimeter-wave and X 1 ⌺ ϩ (v ϭ 0-3) infrared data available in the literature were merged with our new electronic data in order to obtain improved Dunham constants for the ground state of CaO. Very peculiar perturbations are observed in the higher vibrational levels of the AЈ 1 ⌸ state, so the upper levels of transitions with vЈ ϭ 2 and 3 were represented by term values in our least-squares analysis. The interaction of the AЈ 1 ⌸ (v Ն 2) levels with the nearby b 3 ⌺ ϩ (v-2) levels has been detected. An extended set of AЈ 1 ⌸ (v ϭ 0-3) data has been obtained which is suitable for use in a future multistate deperturbation analysis of the a 3 ⌸ ϳ AЈ 1 ⌸ ϳ b 3 ⌺ ϩ ϳ A 1 ⌺ ϩ complex of excited states. The new near-infrared spectra of the AЈ 1 ⌸-X 1 ⌺ ϩ transition of CaO also permits the first direct high-resolution linkage between the orange and green systems and the near-infrared bands.