V+(H2O)Ar-n and V+(D2O)Ar-n complexes are studied with mass-selected infrared photodissociation spectroscopy in the O-H (O-D) stretch region. Two vibrational bands are measured 50-80 cm(-1) to the red from the symmetric and asymmetric stretches in free water. Rotational analysis for V+(H2O)Ar indicates a C-2upsilon geometry with argon opposite water and significant expansion of the H-O-H angle. The upsilon = 1 level in the asymmetric stretch undergoes distortion consistent with selective excitation into the coordinate of an insertion reaction. (C) 2003 American Institute of Physics.