INTERSYSTEM-CROSSING AND EXCITED-STATE ABSORPTION OF C-70 STUDIED BY PICOSECOND PUMP AND PROBE ABSORPTION AND FLUORESCENCE MEASUREMENTS

The singlet and triplet absorption and emission dynamics of C-70 in to luene is studied with a picosecond Nd:glass laser double-pulse pump an d probe transmission and fluorescence measurement technique. The singl et S-1 excited-state absorption (sigma(ex,L) approximate to 6 x 10(-17 ) cm(2)), the triplet T-1 absorption (sigma(T )approximate to 4.2 x 10 (-17) cm(2)), and the triplet T-2 absorption (sigma(ex,T) approximate to 4.3 x 10(-17 )cm(2)) at 527 nm are determined. The singlet to tripl et intersystem-crossing is studied by double pump pulse induced fluore scence signal analysis and by double probe pulse transmission measurem ents. The yield of triplet formation is found to be near to unity. (C) 1998 Elsevier Science S.A. All rights reserved.