Microsolvation of the lithium ion by methanol in the gas phase

Electrospray ionization (ESI) has been employed to produce Li+(CH3OH)m for infrared spectroscopic studies using a vibrational predissociation spectrometer. A gradual blue shift of the CO stretching frequency from 1023 cm−1 to 1027 cm−1 was observed as m increases from 5 to 10, supporting the suggestion for the formation of the second solvation-shell in Li+(CH3OH)5, in accord with the prediction by density functional theory calculations performed at the B3LYP/6-311+G**//6-31+G* level. We demonstrate in this work that the ESI source is applicable not only to the infrared study of Li+(CH3OH)m but also to other alkali metal methanol cluster ions as well.