Determination of the Transition-Moment Directions from Photoselection in Partially Oriented Systems

Abstract

A formula is derived for the emission anisotropy r(β, Rs) of a polymer film as a function of the stretch ratio Rs of the film and of the angle β between the absorbing and emitting oscillators for the case when the long axis of the molecule makes an angle φ = 90° with the absorbing oscillator. This relation is verified, together with that obtained previously for φ = 0°, on the example of acridone and anthracene in polyvinyl alcohol. The experimental results obtained for r(β, Rs) as a function of Rs confirm the character of the predicted theoretical curves. The reasons for the lack of quantitative agreement is also discussed.

Fluorescence measurements: importance of G-factor correction, magic angle, and observation wavelengths

“…This is due to the averaged cos 2 ω probability for light absorption. (An interested reader can see details of averaging in [6] or original publications [17][18][19]). Due to angle dependent probability for light absorption by the dipole (the process called photoselection) the intensity ratio of I I…”