## Abstract

The A'(1)Pi(1)Sigma(+) near-infrared system of CaO was observed for the first time at high resolution using a Fourier transform spectrometer. The A'(1)Pi-X'Sigma(+) chemiluminescence was excited in a Ca + N2O flame produced in a Broida-type oven. More than 3000 rotational lines, classified into 19 bands involving the A'1 Pi 0 less than or equal to nu' less than or equal to 3 and the X(1)Sigma(+) 1 less than or equal to nu" less than or equal to 7 vibrational levels were measured in the 4000-10 000 cm(-1) region with a precision of 0.005 cm(-1). The X(1)Sigma(+) (nu = 0, 1) millimeter-wave and X(1)Sigma(+) (v = 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 A'(1)Pi state, so the upper levels of transitions with nu' = 2 and 3 were represented by term values in our least-squares analysis. The interaction of the A'(1)Pi (nu greater than or equal to 2) levels with the nearby b(3)Sigma(+) (nu-2) levels has been detected. An extended set of A'(1)Pi (nu = 0-3) data has been obtained which is suitable for use in a future multistate departurbation analysis of the a(3)Pi similar to A'(1)Pi similar to b(3)Sigma(+) similar to A(1)Sigma(+) complex of excited states. The new near-infrared spectra of the A'(1)Pi-X-1 Sigma(+) transition of CaO also permits the first direct high-resolution linkage between the orange and green systems and the near-infrared bands. (C) 2000 Academic Press.

Original language | English |
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Pages (from-to) | 330-338 |

Number of pages | 9 |

Journal | JOURNAL OF MOLECULAR SPECTROSCOPY |

Volume | 203 |

Issue number | 2 |

Publication status | Published - Oct 2000 |

## Keywords

- FTIR EMISSION-SPECTRA
- MOLECULAR-CONSTANTS
- ELECTRONIC-STRUCTURE
- POTENTIAL CURVE
- ALKALINE-EARTH
- METAL-OXIDES
- BANDS
- SRO
- BAO
- DEPERTURBATION