Photochemistry and solvation of HI(H2O)n clusters: Evidence of biradical formation

During the course of investigating the solvation and photochemical dynamics of HI(H2O)n clusters employing a pump–probe technique, we observed unusual behavior associated with iodine atoms dissociating from the HI(H2O)n clusters, displaying different time responses than for the case of the HI monomer or HI clusters. Further experimentation provided experimental evidence for a theoretically predicted biradical species which consists of a halo-acid clustered to water molecules. In addition, as a side issue, we discuss our results in conjunction with others that point to a possible alternative explanation compared to the traditionally accepted one for the phenomena known as the solvated electron.