REACTION OF [XE-F](+) WITH HI

The reaction behavior of [XeF][AsF6] in solution toward hydrogen iodid e, HI, was investigated and Xe, HF, and [I-4][AsF6](2) were identified as the final reaction products. The reaction enthalpy of the gas-phas e reaction ([XeF](+) + HI --> [XeI](+) ((1) Sigma) + HF) was calculate d at the optimized MP4(SDQ) geometries at the QCISD (TQ) level to be: Delta H-298(0) [QCISD (TQ)/LANL2DZ//MP4(SDQ)/LANL2DZ] = -63.3 kcal mol (-1). The [XeI](+) cation is bound only in the (1) Sigma singlet state , and the triplet state (3 Pi) was shown to be essentially unbound at all levels of theory applied and very close in energy to the singlet s tate at equilibrium structure. According to the ab initio calculations , [XeI](+) can react with HI in a thermodynamically and spin-symmetry allowed reaction to yield the [XeI](+) ((1) Sigma) cation that may, af ter interconversion into the unbound triplet stare, immediately dissoc iate into xenon (S-1) and I+ (P-3). (C) 1997 John Wiley & Sons, Inc.