Pseudopotential Scf-mo Studies of Hypervalent Compounds

The (ab initio) effective potential method developed previously has been applied to several molecules in order to establish a basis set and effective potential for iodine and to examine aspects of the potential surfaces of hypervalent compounds of iodine. Implied lone-pair stereochemical activity is found to agree well with experiment. Results for the structures and force constants closely resemble those found in related studies of xenon fluorides which exhibit similar systematic deviations from experiment. Iodinefluorine bond lengths are overestimated by about 0.05 A and stretching force constants are slightly too high. These data provide a consistent basis for investigating further aspects of hypervalent iodine compounds that have so far resisted experimental resolution.