J-aggregation and disaggregation of indocyanine green in water

J-aggregates of indocyanine green sodium iodide in water are formed by heat treatment. Starting from a dimeric solution the activation energy of molecule attachment (E_att ≈ 0.41 ev) to J-aggregates is determined by analysing the temperature dependence of the rate of J-aggregate absorption growth. The activation energy of molecule detachment (E_det ≈ 0.51 eV) from J-aggregates is deduced from the temperature dependent rate of J-aggregate absorption decrease after strong dilution.