This award will support Professor C. Denise Caldwell of the University of Central Florida in a research collaboration with Professor J. Jimenez-Mier of the Universidad Nacional Autonoma de Mexico (UNAM). The investigators intend to measure the alignment of photoions as determined through the angular distribution of decay fluorescence. The experiments will be performed at the University of Wisconsin Synchrotron Radiation Center with an apparatus that has been specifically constructed for performing this type of experiment. The experimental effort will be joined by the investigator from Mexico, who will be responsible for all data analysis and analytic interpretation. Measurement of alignment of photoions by fluorescence analysis is a relative newcomer to the group of techniques that are available for study of electron-electron correlation. Due to its sensitivity to effects of this interaction, it has the potential of becoming a powerful tool, especially for analysis at thresholds. In addition to the application of this technique to the study of various systems, the investigators will try to interpret its measurements in terms of existing theories.