MICROSOLVATION OF THE AMMONIUM ION IN ARGON - INFRARED-SPECTRA OF NH4-AR-N COMPLEXES (N = 1-7)()

Infrared spectra of mass selected NH4+-Ar-n (n = 1-7) cluster ions hav e been recorded in the range between 3000 and 3500 cm(-1) by means of photodissociation spectroscopy. Vibrational assignments are based on a b initio calculations by taking into account complexation-induced freq uency shifts and splittings as well as band intensities. The results i ndicate that the first four Ar atoms occupy equivalent vertex-bound si tes, while further Ar atoms are probably located at the faces of the t etrahedral monomer. (C) 1997 Elsevier Science B.V. (C) 1997 Elsevier S cience B.V.