Infrared multiple photon dissociation spectra of methanol-attached anions and proton-bound dimer cations

The infrared absorption spectra of several gas-phase ions solvated by a single methanol molecule have been determined indirectly by infrared multiple photon dissociation (IRMPD) spectroscopy. A modified White-type multi-pass cell was used in a Fourier transform ion cyclotron resonance mass spectrometer to record the disappearance of the parent ion as a function of the wavelength of a tunable CO2 laser operating in the range of 920-1060 cm(-1). Spectra were obtained for fluoride, chloride and methoxide anions to which either a methanol or a d-methanol molecule was attached. In addition, spectra of proton-bound methanol and d-methanol dimer cations are presented. The shifts in the IRMPD peak frequencies are compared with the respective neutral infrared spectra. A consistent and interesting splitting is observed in the case of ions to which a methanol-d(1) molecule is attached.