Improved Molecular Constants for the Ground State of DO2

✍ Scribed by K.V. Chance; D.A. Ramsay; E.H. Fink

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 32 KB
• Volume: 207
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2001.8310

✦ Synopsis

NOTE Improved Molecular Constants for the Ground State of DO 2

Molecular constants for the ground state of DO 2 are redetermined using a combined analysis of previously published microwave measurements (1) and combination differences from a rotational analysis of the 000 -000 band of the à 2 A → X 2 A electronic transition in the 7000 cm -1 region (2). The analysis method follows on that used previously for HO 2 (3), and employs the parameterized Hamiltonian given in Ref. ( ). The microwave measurements include 58 lines, from 51 to 196 GHz, with rotational levels up to N = 7, K a = 2. The line at 74.579170 GHz was omitted from the fitting, as in Ref.

(1). The line at 114.657274 GHz is reassigned as an unresolved combination of F -F = 5/2 -7/2 and 3/2 -5/2; the line at 143.160834 GHz is reassigned as F -F = 15/2 -13/2; 174 combination differences for rotational levels up to N = 31, K a = 9 from the à 2 A → X 2 A band are used in the analysis.

A revised set of molecular constants is obtained by combining both sets of data with appropriate weightings, where the combination differences are assigned uncertainties of 0.003 cm -1 and the microwave measurement uncertainties are taken from Ref. (1), and refitting to the parameterized Hamiltonian. Since the combination differences do not resolve the hyperfine structure, the hyperfine terms a F , T 2 0 , T 2 1 , and T 2 2 in the parameterized Hamiltonian were first determined using only the microwave lines, and then fixed to these values in the final fitting analysis. The weighted RMS of the fit is 1.15. The molecular constants are given in Table .

An attempt was made to also include the millimeter-wave (field-free) measurements from Ref. (5) in the combined analysis. It was found that significantly