ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The A 1Σ+–X 1Σ+ emission spectrum of BaO excited in a Broida-type oven was revisited using a Fourier transform spectrometer. Chemiluminescence was observed from excited BaO molecules generated from the Ba+N2O reaction, and 82 vibrational bands of 138BaO were measured in the range 8900–21 000 cm−1 at a resolution of 0.04 cm−1. Vibrational levels were observed up to v″=20 of the ground state and up to v′=11 for the excited state. In addition, 72 bands from the minor isotopomers 137BaO, 136BaO, and 135BaO were detected with v″ up to 14 and v′ up to 4. Over 15 500 lines with J″ up to 119 were measured with a precision of about 0.005 cm−1, which shows that the Broida oven is an excellent source for high-resolution emission spectroscopy. Our main goal here is to obtain an optimum set of molecular constants for the ground electronic state. To avoid complications due to the well-known perturbations for vA′≥1 of the A 1Σ+ state, our unified combined-isotopomer analysis used a novel combination of a Dunham expansion description of the ground state with independent band-constants for data involving A-state level vA′=0, while fitting to an independent term value for each observed A-state vA′≥1 vibration–rotation level of each isotopomer. Significantly improved ground-state constants and A-state vA′=0 band constants are obtained, together with term values for some 1372 higher-v′ A-state levels. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1286977
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