Doppler-free DFWM Spectroscopy as a Probe of Photodissociation Dynamics

Abstract

Degenerate Four-Wave Mixing (DFWM) spectroscopy has been used to probe the dynamics of photodissociation induced by 266nm excitation of hydrogen peroxide. Spectra recorded for the nascent photofragments exhibit signal-to-noise ratios that are superior to those reported by previous laser-induced fluorescence studies. In addition, the spatial selectivity associated with the Doppler-free nature of this nonlinear optical process has enabled the determination of quantum state-specific angular distributions for the OH radical products. An effective anisotropy parameter of $\beta_{eff} = -0.63 \pm 0.15$ has been obtained, a value in good agreement with that derived from earlier measurements based upon the deconvolution of Doppler profiles.