Methyl iodide clusters (CH3I)(n) in a supersonic jet are photolyzed in an excitation of the valence A band with a tunable ultraviolet light source, and the iodine molecule (I-2) thus produced is detected by cavity ring-down (CRD) spectroscopy. A production yield of I-2 is measured in the region of 245-275 nm to obtain photofragment excitation (PHOFEX) spectra of (CH3I)(n). The PHOFEX spectra show maximum at 250 nm (similar to1000 cm(-1) blueshifted from monomer) at low concentration, and a new peak at 260-265 nm (similar to450 cm(-1) redshifted) at high concentration. These two peaks are assigned to dimer and higher cluster (hexamer to decamer), respectively, based on our infrared-CRD study [Chem. Phys. 286, 337 (2003)]. The redshifted peak of the higher clusters indicates that perturbation of the excited state due to intermolecular interaction is stronger than in the dimer. (C) 2003 American Institute of Physics.