\\ Species Tag:        &   32005 & Name:&  O2-snglt-dlta
\\ Version:            &       2 & &Oxygen molecule,
\\ Date:       & Feb. 2010       & &metastable $a\;^1\Delta_g$ state
\\ Contributor:&  H. S. P. M\"uller    & &
\\             &                 & &
\\ Lines Listed:       &      52 & Q(300.0)=&      149.5718
\\ Freq. (GHz) $<$     &    4495 & Q(225.0)=&      112.7410
\\ Max. J:             &      54 & Q(150.0)=&       75.9346
\\ LOGSTR0=            &   -10.0 & Q(75.00)=&       39.1666
\\ LOGSTR1=            &   -20.0 & Q(37.50)=&       20.8328
\\ Isotope Corr.:      &     0.0 & Q(18.75)=&       11.7544
\\ Egy. (cm$^{-1}$) $>$&  7882.4 & Q(9.375)=&        7.3900
\\ $\mu_a$ = &                   & A=&
\\ $\mu_b$ = & magnetic          & B=&  42504.52
\\ $\mu_c$ = &                   & C=&
\headend

This is a combined CDMS/JPL catalog entry. The $a\;^1\Delta_g$ 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. M\"uller, F. Lewen, S. Br\"unken, and H. Habara,
2010, J. Quant. Spectrosc. Radiat. Transfer (in press). 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. {\bf 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. {\bf 54}, 330