ANALYSIS OF THE THIRD-ORDER SUSCEPTIBILITIES OF TRIPLET EXCITED MOLECULES USING NANOSECOND TIME-RESOLVED RESONANCE CARS

Nanosecond time-resolved resonance CARS spectra of anthracene and 9,10-dichloroanthracene in the lowest excited triplet state are reported. Simultaneous fitting of a series of time-resolved CARS spectra to appropriate lineshape equations was used to determine the molecular third-order susceptibility parameters of these electronic excited state molecules unambiguously. The capability of this method to study the resonance behaviour of these parameters is demonstrated by the determination of the sign of the imaginary part I of the Raman resonant CARS susceptibility of T1 triplet anthracene at two different pump laser wavelengths. © 1998 John Wiley & Sons.