Infrared spectroscopy of the Ti(H2O)Ar+ ion–molecule complex: Electronic state switching induced by argon.

Titanium–water complexes are produced by laser vaporization in a pulsed supersonic expansion, mass selected in a time-of-flight spectrometer, and studied with infrared laser photodissociation spectroscopy using argon complex predissociation. Density functional theory calculations provide structures and vibrational spectra for these ions. Spectra in the O–H stretching region indicate that the water is intact in these complexes, even though inserted structures are computed to be more stable. Although the ground state of Ti(H 2 O) + is established to be a quartet, that predicted and observed for Ti(H 2 O)Ar + is a doublet. Attachment of argon changes the electronic ground state of this system. [ABSTRACT FROM AUTHOR]