Stimulated Emission from Normally Non-fluorescent T.I.C.T. States of 7-DAMC

Abstract

The 7 amino coumarins are an important class of laser dyes in the blue green spectral region. The dye 7 DAMC is an example of this class of dyes which has an amine moiety at the seventh position unrestricted by any substituent linkage. On optical excitation this dye can exist in the excited state in two different molecular conformations. The first excited conformation B* is a moderately polar, planar, intramolecular charge transfer (ICT) state and the other excited conformation A* obtained by rotation of the amine moiety at the seventh position leads to a non planar, highly polar, twisted intra molecular charge transfer (TICT) state. Both these ICT and TICT states are stabilized by substituents which are electron donating at the nitrogen site and on the aniline ring and electron withdrawing on the lactone ring, and also by solvent dipoles including specific interactions such as bonding.KeywordsLaser TransitionIntramo1ecu1ar Charge TransferButyl AcetateAmine MoietySolvent DipoleThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.