This research program is in the areas of picosecond time-resolved Raman studies of semiconductors, semiconductor multiple quantum well (MQW) structures and energy transfer of electronic and molecular defects in ionic crystals. The program is divided into three sub-programs: (1) transport properties of the photoexcited electron-hole plasma (EHP) in semiconductors and semiconductor MQW structures, (2) electron-phonon and phonon-phonon interactions and deep impurities in semiconductor MQW structures, and (3) transient energy transfer of electronic and molecular defects in alkali halides.