Comments on the determination of excited state dipole moment of molecules using the method of solvatochromism.

The present note comments on several publications which appeared in different journals containing many inaccurate statements and lacking honest citations of basic papers dealing with the application of solvatochromism to determine excited state dipole moments.

Nonradiative excitation energy transport in one-component disordered systems.

High-accuracy Monte Carlo simulations of the time-dependent excitation probabilityG (s) (t) and steady-state emission anisotropyr M /r 0M for one-component three-dimensional systems were performed. It was found that the values ofr M /r 0M obtained for the averaged orientation factor[Formula: see text] only slightly overrate those obtained for the real values of the orientation factor κ ik (2) . This result is essentially different from that previously reported.

The influence of rotational depolarization on the mechanism of energy transport in two-component systems: The nature of correlations.

The correlation effect in two-component systems of different viscosities was analyzed based on a concentration depolarization experiment. The inclusion of a correlation effect was found to be fully justified only in systems for which the localization time, τl, is considerably shorter than that of the rotational relaxation, τrot. On the grounds of an approximate analysis, taking into account the competition between the concentration and the rotational depolarization, it was possible to explain the concentration changes in the emission anisotropy in the systems investigated.

The influence of reverse energy transport on emission anisotropy in two-component viscous solutions.

The effect of nonradiative reverse energy transport (NRET) in two donor-acceptor systems was studied experimentally. It was found that the NRET occurring in system I; rhodamine 6G (donor) and rhodamine B (acceptor), considerably lowers the emission anisotropy at medium and high concentrations. These results qualitatively confirm the predictions of the approximate theoretical approach of L.

Absorption and luminescence spectroscopic analysis of tautomeric forms of protonatedN,N-dimethyl-N'-(1-nitro-9-acridinyl)-1,3-propanediamine (nitracrine) and its nitro isomers in poly(vinyl alcohol) films.

The electronic absorption, fluorescence, and phosphorescence excitation spectra, as well as the fluorescence and phosphorescence spectra, at either room or liquid nitrogen temperatures, were measured forN,N-dimethyl-N'-(1-nitro-9-acridinyl)-1,3-propanediamine and its three nitro isomers in acidified poly(vinyl alcohol) (PVA) film. The spectral characteristics obtained reveal the existence of the compounds studied in at least two structural forms. The results are interpreted in terms of the tautomeric phenomena which originate due to the migration of the hydrogen atom, which is bound to the nitrogen atom attached to the carbon atom (9), to the acridine ring nitrogen.