GROUND-STATE AND EXCITED-STATE ROTATIONAL-CONSTANTS OF P-CYCLOHEXYLANILINE

Picosecond time-correlated single-photon counting spectroscopy has been used in rotational coherence measurements to determine the excited-state moments of inertia of p-cyclohexylaniline. This work complements earlier experiments involving single-color time-resolved fluorescence depletion spectroscopy, allowing the separation and identification of the rotational constants in the S0 and S1 states. Simulations have shown that the persistence of the K-type recurrences over several dozen cycles is consistent with a difference of almost-equal-to 2% between the excited-state B and C constants. The final results were as follows: (ground state) A'' = 2410 MHz, (B'' + C'') = 725 MHz; (excited state) A' = 2355 +/- 15 MHz, B' = 365 +/- 4 MHz, C'= 360 +/- 4 MHz.