THE EFFECT OF PRESSURE, TIME AND CONCENTRATION IN HOLE-BURNING STUDIES

The effective homogeneous line width Gamma(kom)(') of the S-1 <-- S-0 0-0 transitions of bacteriochlorophyll-a (BChl-a) in the glass triethy lamine (TEA) and of free-base chlorin (H(2)Ch) in polystyrene (PS) hav e been studied, respectively, under the influence of high pressure (si milar to 30 kbar) and for a range of concentrations (similar to 10(-4) -10(-2) M). The aim was to get a better understanding of spectral diff usion and energy transfer processes in amorphous systems. The dependen ce of Gamma(kom)(') on temperature (1.2-4.2 K), excitation wavelength (within the 0-0 band) and delay time (10(-6)-10(5) s) was measured for both systems by means of spectral hole burning.