Picosecond absorption studies of intermolecular electronic energy transfer in micellar systems. II. Polarization-dependent studies of energy migration and energy trapping at low donor excitation densities

Photophysics and Mechanisms of Intramolecular Electronic Energy Transfer in Bichromophoric Molecular Systems: Solution and Supersonic Jet Studies

“…Fo ¨rster theory and its many extensions (see below) are ideally suited for quantitative interpretation and prediction of experimental observations of inter-EET in systems ranging from dye solutions and ETDL systems, [44][45][46][47][48][49][50][82][83][84][85][86][87][88][89][90][91][92][93] polymers, [60][61][62][63][64][94][95][96] molecules adsorbed on surfaces, [97][98][99][100][101][102] transfer between monolayers and monolayer assemblies, [103][104][105] in Langmuir-Blodget films, [106][107][108][109][110] in micellar solutions [111][112][113] to restricted geometries, fractals, and disordered systems. [114][115][116][117]…”

“…The validity of eq 34 was demonstrated for many molecular systems, even for inter-EET on a picosecond time scale, 112,113,[130][131][132][133][134][135][136][137][138][139][140][141] thus establishing the applicability of Fo ¨rster's theory. However, even in such media, modifications, based on the general theory of radiationless transitions, are needed to discuss temperature dependence and isotope effects of the EET rate.…”

“…For such transitions the critical transfer radii values range between 10 and 100 Å . This range of values depends on the intensities of the relevant electronic transitions of D and A as well as on their spectral overlap, as expressed by the spectral overlap integral for dipole−dipole interaction Förster theory and its many extensions (see below) are ideally suited for quantitative interpretation and prediction of experimental observations of inter-EET in systems ranging from dye solutions and ETDL systems, − ,− polymers, − ,− molecules adsorbed on surfaces, − transfer between monolayers and monolayer assemblies, − in Langmuir−Blodget films, − in micellar solutions − to restricted geometries, fractals, and disordered systems. − For describing EET involving forbidden transitions one should consider exchange interaction contributions, as discussed in the next section.…”

Picosecond absorption studies of intermolecular electronic energy transfer in micellar systems. 1. Inhomogeneous spatial distribution and indirect donor-donor interaction

“…In a low-intensity ET experiment one would expect the effect of donor competition to be negligibly small as it is confirmed in ps dye laser experiments. 44 On the other hand, for a short-lived acceptor (rA « rD) the indirect donor-donor interaction should disappear also in a high donor excitation density experiment. Measurements with MG as acceptor indeed revealed no significant dependence of r¡T on the average donor number [Table II, Figure 8 (bottom)].…”

“…Low-intensity investigations as well as polarization-dependent experiments will be presented in a subsequent paper. 44 The very rapid ET in micelles as well as its high efficiency holds promising possibilities for an application in ps dye laser design. In particular, a micellar ET dye mixture can be advantageously used in short cavity dye lasers for short-pulse generation.…”