O2, a 1Δ
Oxygen, a 1Δ
Species tag 032510
Date of EntryFeb. 2010
ContributorH. S. P. Müller

This is a combined CDMS/JPL catalog entry. The a 1Δ electronic state is the second lowest electronic state, almost 8000 cm–1 above ground. It is metastable, fairly long-lived. Transitions in a discharge environment can be fairly strong.
The data have been summarized in
(1) B. J. Drouin, S. Yu, C. E. Miller, H. S. P. Müller, F. Lewen, S. Brünken, and H. Habara, 2010, J. Quant. Spectrosc. Radiat. Transfer 111, 1167
This work provides new data between 0.84 and 1.95 THz. Additional data were taken from
(2) K. W. Hillig, C. C. W. Chiu, W. G. Read, and E. A. Cohen, 1985, J. Mol. Spectrosc. 109, 205
For multiply measured transitions differing in uncertainties by less than a factor of 2 weighted averaged have been derived.
Predictions should be viewed with caution above ~3 THz.
The partition function was calculated as if the lowest rotational level were at an energy of zero. The state is basically unpopulated at thermal equilibrium.
Intensities were calculated based on g values obtained by magnetic resonance by
(3) T. A. Miller, 1971, J. Chem. Phys., 54, 330

Lines Listed52
Frequency / GHz< 4495
Max. J54
log STR0-10.0
log STR1-20.0
Isotope Corr.-0.0
Egy / cm–1(7882.4)
 µa / D 
 µb / D 
 µc / D 
 A / MHz 
 B / MHz42504.52
 C / MHz 
detected in ISM/CSMno

Database maintained by Holger S. P. Müller and Sven Thorwirth, programming by D. Roth and F. Schloeder