Detection of O(1D) Produced in the Photodissociation of O2 in the Schumann−Runge Continuum

O(1D) produced from O2 by photodissociation in the Schumann−Runge continuum was studied. The metastable atom O(1D) was detected by observing the 762 nm fluorescence from O2(b 1∑g +) generated by the energy transfer process O(1D) + O2 → O + O2(b 1∑g +). A quantum yield of unity was found in the wavelength range 139−175 nm. O(1D) was detected at wavelengths longer than the threshold at 175 nm with reduced quantum yields due to excitations of molecules in the high rotational states. The quantum yields vary from 1 in the range 130−139 nm, resulting from crossing of the state 3∑u - with 3Πu. The absorption spectra for both states were determined. The peaks for maxima and minima absorptions were compared with previous experimental and theoretical results.