According to Förster's energy transfer mechanism the energy transfer from acriflavine to 5

10-b.is (P-aminenyl)-l5-20-bispheny]porphin (TBP) and sensitive luminescence of TBP in chloroform solution have been studied by luminescence spectroscopy. The results show that the energy transfer from acriflavine to TBP can be explained simply in terms of Förster's energy transfer mechanism.In the present system we have found that R value of critical trans-fer distance for the donor (acriflavine)-acceptor (TBP) system equals to 0.42nm and the energy transfer effeciency is about 0.72. When the concentration of acceptor increased the lifetime of the donor decreased and the transfer rate increased.The transfer rate given in Table 1 have been calculated from the lifetimes obtained by fitting the date with single exponential decay. From Table i it is clear that the transfer rate is increased from 1.07×10

7

S

-1

to 1.42×

10

S

-1

.Therefore

it is concluded that in the present system energy transfer from donor to acceptor at this concentration is governed by Förster's energy transfer theory.