Optical response of a spherically confined exciton with the effects of e-hexchange and image charge density

A thorough theoretical study has been made on the optical response of an ex citon weakly confined in a sphere over a wide range of size, based on the p revious work on the exciton level scheme which takes account of electron-ho le ir-h) exchange interaction, size quantized center-of-mass (CM) motion, a nd the effect of background polarization. In the presence of transverse EM field, the cross section of elastically scattered light has been calculated according to a modified microscopic nonfocal response theory. Tile results allow us a systematic understanding of resonant spectral structure in a wi de range of sample size, in relation with the corresponding level scheme, r adiative shift and width, and the longitudinal and transverse character of each exciton level.