Abstract :
The theory of molecular excitons in one-dimensional (1-D) crystals with 3-D entities is developed as a modification of the existent theory (for 3-D crystals), starting from a settlement of the 1-D space group. Then, it is applied to one of the helix models of the PIC J aggregates, as postulated, to interpret various experimental facts, such as the importance of hydrophobic groups and evidence of a core, i.e. a building block with (at least) 8 PIC molecules. Through the development of a formalism, the absorption and rotation of light by a helix with more than two spirals (2 × 4 = 8 spirals corresponding to 4 double linear arrays, actually) are estimated and found to be consistent with the observed polarized absorption and circular dichroic spectra of the aggregates.
