Photoionization of the primary photoproducts of A(2∏)-excited ClO

Abstract

Photoionization of the primary photofragments of chlorine monoxide (ClO) is reported. ClO is photolyzed in the X(2∏)→A(2∏)-regime, yielding Cl(2P) and O(3P,1D). The primary photolysis products, as well as the not photolyzed ClO, are subsequently probed by monochromatic, time-correlated vacuum-ultraviolet radiation from a laser produced plasma source. Autoionization is used for state-specific detection of the atomic photolysis products. The formation of O(3P) is exclusively observed above ≈264 nm. The threshold of O(1D) from A(2∏3/2)-excited ClO is found at 263.71±0.01 nm. The shape of the O(1D) yield near this threshold is discussed in terms of the rotational energy distribution and a rotational barrier of A(2∏3/2)-excited ClO. Direct (nonresonant) one-photon-ionization is used to establish the absolute photoionization cross sections of ClO(X(2∏)), Cl(2P), and O(1D) near 15 eV. Additional experiments on the UV-photolysis of Cl2, yielding Cl(2P), are consistent with the results on ClO. The present work is compared to earlier experimental and theoretical studies.