Time-Resolved Spontaneous Raman Scattering by Chrysene in S1 and T1 and Time-Resolved CSRS with the use of Incoherent Light

Time-resolved S n -S 1 and T n -T 1 resonance Raman spectra of highly purified chrysene in tetrahydrofuran were observed at room temperature. Raman lines attributed to S 1 were observed at 1549, 1369, 1344, 1110, and 990 cm -1 and to T 1 at 1528, 1494, 1353, 1199, 1110, 990, 678, 554, 472, and 286 cm -1 . The decay time of the intensity of 1369 cm -1 (S 1 ) line and the formation time of 1199 cm -1 (T 1 ) line were obtained to be https://www.w3.org/1998/Math/MathML" display="inline"> 35 - 5 + 6 ns and https://www.w3.org/1998/Math/MathML" display="inline"> 41 - 7 + 10 ns, respectively. Discussion was made on the geometrical changes in the excited states from the intensities of these lines. We applied incoherent laser for the measurement of T 2 (=γ 2 -1 ) by CSRS, we call them incoherent CSRS. Using two light sources (E(t) at ω L and E AS (t) at ω AS ), one of which is incoherent light with correlation time https://www.w3.org/1998/Math/MathML" display="inline"> Γ C - 1 and split into two beams with delay time τ (E 1 (t)=E 2 (t+τ)=E(t), exp(-Γ c |t-s|)), we can obtain the intensity of CSRS (I(τ)) at 2ω L -ω AS from which we can determine T 2 between subpicosecond and a few picosecond.