Time-, wavelength, and polarization-resolved measurements of OH (A (2)Sigma(+)) picosecond laser-induced fluorescence in atmospheric-pressure flames

Laser-induced fluorescence of OH (A (2)Sigma(+), upsilon' = 1) was measured in hydrogen/oxygen and hydrogen/air/nitrogen flames using laser pulses of 80 psec duration. A 2D signal acquisition scheme simultaneously employed wa velength, temporal, and polarization resolution. The signals emitted in dif ferent rotational branches exhibit polarization-dependent intensities, depe nding on the rotational branch of the absorption line used. It is possible to select experimental conditions such that rotational and vibrational rela xation as well as electronic quenching can be monitored simultaneously. Adv antages and limitations of the experimental approach are discussed. Numeric al simulations are presented of the LIF spectra affected by energy transfer .