Fluorescence polarization in pyrazine, pyrimidine, and <i>s</i>-triazine in the vapor phase

Abstract

The fluorescence polarization in the vapor phase has been observed for excitation along the rotational contour of the 0–0 bands of pyrazine and pyrimidine and the 610 and 620 bands of s-triazine in the S0→S1 transition. In all the cases, the resonance fluorescence exhibits a remarkable variation in the degree of polarization along the rotational contour, with larger values for the Q branch excitation than for the R or P branch excitation. On the other hand, the broad emission of s-triazine vapor originating from levels to which a nonradiative transition occurs from the initially prepared vibronic level does not show polarization.