Competition Between Two Excitation-dissociation Channels for Molecular Ions

When the molecular ions XYZ(+) (XY2+) are excited simultaneously from an electronic state E-0 into two higher electronic states E-alpha and E-beta with supervened dissociation or predissociation, competition between the alpha and beta excitation-dissociation channels occurs. A theoretical model is provided to deal with the competition of the two excitation-dissociation channels with more than two kinds of ionic products for XYZ(+) (XY2+). Supposing that the photo-excitation rates of two states E-alpha and E-beta are much less than their dissociation or pre-dissociation rates, a theoretical call be deduced to fit the measured data which reflects the dependence of the, product branching ratios on the intensity ratios of two excitation lasers. From the fitted parameters the excitation cross section ratios are obtained. In experiment. we studied the competition between two excitation-dissociation channels of CO2+. By measuring the dependence, of the product, branching ratio on the intensity ratio of two dissociation lasers and fitting the experiment data, with the theoretical equation, excitation cross section ratios were deduced.