Improved Molecular Constants for the Ground State of HO2

✍ Scribed by K.V. Chance; K. Park; K.M. Evenson; L.R. Zink; F. Stroh; E.H. Fink; D.A. Ramsay

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 76 KB
• Volume: 183
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1997.7282

✦ Synopsis

NOTE Improved Molecular Constants for the Ground State of HO 2 Molecular constants for the ground state of HO 2 were recently published TABLE 2

by some of us (1). These constants were based on measurements of the Revised Molecular Constants for the HO 2 Ground State (MHz) frequencies of 17 transitions in the region 2.5 to 5.9 THz combined with Including Combination Differences from A ˜2A r X ˜2AЉ

previously measured microwave and millimeter-wave measurements. Unfortunately it has been found that there was a small error in the computer program used; the off-diagonal spin-rotation matrix element

. This error particularly affected the values fitted for b s , D s NK , d s K , and T 2 1 . Table gives the molecular constants obtained after this correction. In the meantime, a rotational analysis of the 000-000 band of the A ˜2A r X ˜2AЉ electronic transition in the region of 7000 cm 01 (2) revealed systematic discrepancies between observed and calculated ground state combination differences at high values of N and K a . The terahertz, microwave, and millimeter-wave measurements encompassed rotational levels up to N Å 26 and K a Å 5 but the nearinfrared measurements extended to N Å 31 and K a Å 9. The magnitude of the discrepancy for predicting combination differences involving K a Å 7-9 was 0.01-0.04 cm 01 .

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 0.002-0.003 cm 01 , and refitting to the parameterized Hamiltonian. Combination differences (133), involving values of N