摘要
The infrared spectrum of the simplest geminal diol, methanediol or methylene glycol (CH 2 (OH) 2 ), was successfully probed in the gaseous hydration of formaldehyde. The observed absorption bands coincided with the anharmonic vibrational wavenumbers predicted by B3LYP/aug-cc-pVTZ calculation. Based on the predicted rotational parameters and dipole derivatives, the simulated rovibrational contours of CH 2 (OH) 2 agreed with the experimental spectrum, and the band origins of the OCO symmetric stretching mode (b-type) and the OCO asymmetric stretching mode (a-type) were determined to be 1027 and 1058 cm −1 , respectively. In addition, the isotopic analogues, CD 2 (OH) 2 , CH 2 (OD) 2 , and CD 2 (OD) 2 , were also investigated. The band origins of the CD 2 wagging mode (a-type) and the COH bending mode (a, c-type) of CD 2 (OH) 2 were also determined to be 1121 and 1301 cm −1 , respectively. The successful infrared characterization of gaseous methanediol makes it possible to directly investigate the relevant chemical reactions of geminal diols in atmosphere, astrophysics, and water-mediated reactions.