This volume contains the full proceedings of the Fourth International
Workshop on "Desorption Induced by Electronic Transitions" (DIET IV),
held October 2-4, 1989, at the Burghotel Kranichberg, Gloggnitz,
Austria. It followed earlier workshops held in Williamsburg, USA (1982),
SchloB Elmau, FRG (1984), and Shelter Island, USA (1987). The workshop
was attended by 77 participants from 9 countries, and 66 papers (8
invited, 24 oral contributions and 34 poster contributions) were pre-
sented. The proceedings contain 53 separate papers and focus on 8 main
topics: (1) Basic Mechanisms and Theory, (2) Photophysics and
Photochemistry, (3) Laser Induced Desorption, (4) Adsorbed Layers, (5)
Condensed Gases, (6) In- sulators, (7) Gas Phase Processes and (8)
Applications and Related Processes. The workshop was opened by N. Tolk,
who initiated this series of meetings in 1982, and by D. Menzel, who
mentioned the 25th birthday of one of the basic processes in DIET, the
so-called MGR model, which was first published in 1964. One of the goals
of the meeting was to achieve a better understanding and further
improved theoretical descriptions of desorption by electronic
transitions.