Ultrafast Phenomena in Spectroscopy : Springer : 9783642758287 : 3642758282 : 06 Dec 2011 : This volume is a collection of papers presented at the Sixth International Sympo­ sium "Ultrafast Phenomena in Spectroscopy" (UPS '89) held in Neubrandenburg, GDR, August 23-26, 1989. This symposium brought together about 220 scien­ tists from 18 European countries and from overseas. The participants are active in a wide range of scientific disciplines, including physics, chemistry, biology, opto-electronics and scientific instrumentation. They share a common interest in discussing problems and perspectives of ultrafast processes at picosecond and femtosecond time scales. UPS '89 was held eleven years after the first conference of this series, which took place in Tallinn, Estonia. During this period remarkable progress has been made in this field of science and technology. Now the shortest pulses have a duration of about 5 fs, which corresponds to only about three wave periods of visible light.