Feshbach resonances in predissociated states of excited ozone

Rovibronic resonances of ozone in the excited electronic state ${}^{3}{A}_{2}(0,1,0)$ were observed in the high-sensitivity laser cavity ring-down experiment. Accurate measurements of line broadening for several series of transitions permitted to derive predissociation widths and lifetimes of ${}^{3}{A}_{2}$ levels. The rovibrational levels have short lifetimes in the interval 6 to 80 ps due to dissociation towards the quasicontinuum of the ground electronic state ${X}^{1}{A}_{1}$ by the spin-orbit coupling. Analysis of predissociation line broadening in experimental spectra, combined with ab initio calculations of vibrational scattering states, allowed us to assign the resonances as Feshbach-type in the excited ozone. The predissociation is resonantly enhanced by quasibound rovibrational levels of the ${{{\mathrm{O}}_{2}(v=1)\text{\ensuremath{-}}\mathrm{O}}}^{*}$ complex in the ${X}^{1}{A}_{1}\mathrm{state}$, which decay to the ${\mathrm{O}}_{2}(v=0)$-O channel, open at the energy of the resonances.