| This experiments presented in this thesis used an ion time of flight spectrometer to measure the ratio of multiply photoionized to singly photoionized atoms and molecules to observe the electron correlation in those atoms and molecules. The atoms and molecules were photoionized with monochromatized synchrotron light at the Synchrotron Radiation Center. The experiments were done on C60 benzene, sodium and potassium.; The C60 experiment obtained the double, triple, and quadruple ionization thresholds from the double-ionization threshold energy of 19 eV to the inner K-shell of 280 eV. Furthermore, we found modulations in the double-to-single photoionization cross section ratio of C60 which seem to match the inter-molecular distances inside of C60 extremely well. In addition, we also recorded the triple-to-single and quadruple-to-single photoionization cross section ratios, some of them for the first time in published media. Lastly, we also measured the single, double, and triple photoionzation cross sections of C60, on a relative scale.; The benzene experiment was performed between 36 and 180 eV photon energy and recorded the double-to-single photoionization cross section ratio of benzene. This experiment was performed to confirm the existence of the modulations in molecules besides C60, and was successful in finding and linking them to obvious inter-atomic distances within the benzene molecule.; The sodium and potassium experiments were done from near the respective double ionization thresholds of the two elements to 140 eV for sodium and 170 eV for potassium. Both experiments were performed to obtain the double-to-single photoionization cross section ratio of the two elements as a function of photon energy. They were also performed to confirm the existence of a scaling model that seems to work for helium, beryllium, and lithium. The scaling model can be used to predict the shape of the double-to-single photoionization curve for the valence electrons, as well as the maximum value that the ratio will reach. The experiment confirmed that the scaling model works for sodium and potassium, even though their valence electrons were p electrons, and not s electrons as for helium, lithium, and beryllium. |
