|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1994 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Single, double, and triple photoionization of molecules such as NO,CO,CO_2, SO_2, and NO_2 has been investigated by using a multi coincidence (photoelectron-photoion, photoion-photoion, photoelectron-photoion-photoion coincidence) system installed at BL3A2, the UVSOR facility of the Institute for Molecular Science, Okazaki. The following are the interesting results obtained on the production and dissociation dynamics of singly, doubly, and triply charged positive molecular ions using synchrotron radiation.
1.The ratio of double to single photoionization, and the single and double photoionization cross sections were determined for CO_2, SO_2, and NO_2. This made possible to determine separately the ion branching ratios of the precursors m^+ and m^<2+> at the excitation energy where the molecular and dissociative single and double photoionization takes place simultaneously.
2.Kinetic-energy release in the dissociation of m^<2+> was investigated by analyzing the photoion-photoion coincidence spectra from the double photoionization threshold to 100 eV.The results show that a major fraction of double photoionization of small molecules at low energy is due to indirect processes such as the nonresonant (m^<+*>) and resonant (m^<**>) autoionization.
3.The dissociation dynamics of CO_2^<2+> and NO_2^<2+> was examined by using triple photoelectron-photoion-photoion coincidence (PEPIPICO) method. The PEPIPICO method is important to study three-body dissociations whether the dissociation is a simultaneous or sequential process.