Institute of Physics and Astronomy. Aarhus University

In February 1992, the Institute of Physics and the Institute of Astronomy joined under the name of the Institute of Physics and Astronomy (IFA). Therefore, the present Biannual Report describes the research activities within both physics and astronomy during the period from January 1, 1991 to December 31, 1992. During the past two years, the theoretical activities have been strengthened by the installation of a convex C3840 surpercomputer, and the experimental possibilities have increased. The storage ring ASTRID was inaugurated in April, 1991, and is now running according to specifications. As described in the report, among the first successful heavy-ion experiments on the ring are measurements of lifetimes of negative ions, collisions between stored ions and electrons,and collisions between atoms and C60 clusters. For studies using the synchrotron radiation from ASTRID, two monochromatros have been installed, and an x-ray microscope has been successfully tested. Finally, the semiconductor group has put into operation equipment for growing Si-Ge alloys by molecular beam epitaxy. More than 50 brief contributions summarize research in lasers and optical spectroscopy, theoretical atomic physics, semiconductors, thin films, surface physics, condensed matter theory, accelerator mass spectroscopy, radioisotope dating etc. Finally, graduate students, including Ph.D.'s with the title of their theses, the staff, and guest during 1991-1992 are listed. (EG)