15min:

DAVID A. LONG, MITCHIO OKUMURA, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; CHARLES E. MILLER, HERBERT M. PICKETT, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA; DANIEL K. HAVEY, JOSEPH T. HODGES, Process Measurements Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA.

Frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) was utilized to make quantitative laboratory-based measurements of electric quadrupole transitions within the ¹⁶O₂ A -band. We report the first observations of eight extremely weak (line intensities ranging from 3x10^-30 to 2x10^-29 cm molec.^-1) transitions within the NO , PO , and RS branches. New theoretical calculations of line intensities and positions are also presented and compared to these measurements.

\beginwrapfigure[9]i10.5cm \vspace-0cm \hspace*-0cm \epsfigfile=OSU_Quad_Abstract222.eps

\endwrapfigure \newline \mathbfLeft: Measured spectrum (symbols) and Voigt fit (line) of electric quadrupole line in the wings of the PQ(11) hot band, magnetic dipole line. Peak signal-to-noise ratio on electric quadrupole line is 16:1.

\mathbfRight: Fit-derived peak areas vs. number density for the NO branch electric quadrupole lines.