PICOSECOND SPECTROSCOPY OF ELECTRONICALLY EXCITED SINGLET STATES IN BIPHENYLENE

摘要: Abstract The photophysical properties of biphenylene- h 8 and d in solution at room temperature are investigated with picosecond absorption fluorescence spectroscopy. weak complex vibrational structure originates entirely from the S 1 state. It decays monoexponentially a lifetime 240 ± 20 ps. Upon photoexcitation to 2 no emission attributable state was observed. Lifetime quantum yield (Φ F = 2.3 × 10 −4 ) same for completely deuterated compound, indicating that CH vibrations not involved major radiationless decay process level, i.e. internal conversion IC > 0.99). This conclusion is supported by INDO/S CI calculations where strong changes CC bond orders (particularly central C 4 ring) 0 → excitation found. time-resolved excited-state absorption, measured several wavelengths, biexponentially time constants 3 250 40 Various interpretations ps discussed; results transient has be assigned even though expected an allowed transition such long Strong n found as predicted calculations.