Photoelectron spectroscopy and theoretical study of M(IO3)(2)(-) (M = H, Li, Na, K): Structural evolution, optical isomers, and hyperhalogen behavior

H(IO3)(2)(-) and M(IO3)(2)(-) (M = Li, Na, K) anions were successfully produced via electrospray ionization of their corresponding bulk salt solutions, and were characterized by combining negative ion photoelectron spectroscopy and quantum chemical calculations. The experimental vertical detachment energies (VDEs) of M(IO3)(2)(-) (M = H, Li, Na, K) are 6.25, 6.57, 6.60, and 6.51 eV, respectively, and they are much higher than that of IO3- (4.77 eV). The theoretical calculations show that each of these anions has two energetically degenerate optical isomers. It is found that the structure of H(IO3)(2)(-) can be written as IO3- (HIO3), in which the H atom is tightly bound to one of the IO3- groups and forms an iodic acid (HIO3) molecule; while the structures of M(IO3)(2)(-) can be written as (IO3-)M+(IO3-), in which the alkali metal atoms interact with the two IO3- groups almost equally and bridge the two IO3- groups via two O atoms of each IO3- with the two MOOI planes nearly perpendicular to each other. In addition, the high VDEs of M(IO3)(2-) (M = Li, Na, K) can be explained by the hyperhalogen behavior of their neutral counterparts. (C) 2013 AIP Publishing LLC