| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1993: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1992: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Single-, double-, and triple-photoionizatioa processes of gaseous OCS, NO, CO, CO_2 and SO_2 molecules have been investigated using the photolelctron-photoion, photoion-photoion, and photoelectron-photoion-photoion coincidence systems at the UVSOR facility of the Institute for Molecular Science. As a result, much interesting new information was obtained for the production and dissociation dynamics of these singly, doubly, and triply charged molecules. 1. Kinetic-energy release distributions in the dissocia-tion of double charged OCS, NO, and CO was examined in the excitation-energy region from the respective dissociation thresholds to 100 eV.It becomes clear that the production and dissociation of the doubly charged molecular ions are due to the complex mechanism, i.e., the autoionization of superexcited states of neutral and monocationic molecules. 2. Single-, double, and triple-photoionization cross sections of OCS, NO, and CO were determined and further the ion branching rations of singly, doubly, and triply charged parent ions and the respective cross sections of the fragment ions were obtained. The dissociation ratios of the singly, doubly, and triply charged parent ions were also obtained. 3. Dissociation dynamics of doubly and triply charged OCS, SO_2, and CH_3F was studied using the photo-electron-photoion-photoion coincidence method. The mechanism of the threebody dissociation, ABC^<2+> -> A_++B_++C, are independent on the excitation energies between 46 and 80 eV.This result suggests that the three-body dissociation is related to the two site-specific positive holes. 4. Angular distributions of fragment ions (C_++O_+) produced in dissociative double photoionization of CO were observed. The observations of anisotropy in the dissociative double photoionization are discussed in relation to the symmetry considerations involved in the transition. The experimental data for CO_2 and SO_2 a
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