ABSTRACT
Talking about Àuorescence with respect to DNA, one usually refers to Àuorescent labels used extensively inbiologyandgenetics.YetDNAdoesemitÀuorescencealbeitwithalowquantumyield,ontheorder of10−4. Such weak emission, which so far prevented large-scale technological applications, may be preciousinmanyrespectsprovidedthatitspropertiesarewellunderstood.Forexample,itcancontribute toelucidatequestionssuchasthefollowing:Howdidthebuildingblocksofthegeneticcode“survive” whenintenseultraviolet(UV)radiationwasreachingtheearth?Whataretheprimaryeventsleading tophotochemicalreactionsthatinducecarcinogenicmutations?§isispossiblebecausefollowingthe timebehaviorofÀuorescencebringsinformationaboutthesingletelectronicexcitedstatesandtheir relaxation.
