Vibrational study of methylamine dimer and hydrated methylamine complexes in solid neon supported by ab initio calculations

Vibrational study of hydrated methyl formate complexes in solid neon: Observation for the first time of three isomers for methyl formate-water complex

“…For some multiquanta transitions, we can specify assignments. For to the ν 2 +305 combination, at 1911.4 cm -1 , an anharmonicity coefficient X ij of -2 cm -1 can be deduce and this small value for an intra-and an intermolecular mode combination has already been reported for other hydrogen bonding complex [29,30]. For to the ν 1 +ν 2 combinations, the bands at 5166.9 and 5178.5 cm -1 are the combinations of 3572+1608 cm -1 and 3580+1613 cm -1 for the F1 and F2 isomers, respectively (see Table 4).…”

“…As we have previously shown in studies of hydrogen bonding complexes [29][30][31] following the effect of complexation by using the frequency shift between the monomer and complexes (Δν=ν mono -ν complex ) is a good spectroscopic diagnosis to match the observed bands with modes of the different complexes. Also the comparison between observed and calculated data is essential to help the vibrational analysis.…”

Vibrational study of acrylonitrile dimer and acrylonitrile-water hydrogen-bonded complexes in solid neon supported by ab initio calculations

“…Indeed in the 1:1 complex the water molecule is the proton donor as a water molecule in the water dimer and in this case the X 23 anharmonicity coefficient for the  2 + 3 combination is -17.6 cm -1 [20]. Remark is supported by the comparison with results for other hydrogen bonding complex [13][14][15]27] for which the X 23 coefficient values are similar to that of the water dimer within a few cm -1 . Taking into account the water dimer X 23 coefficient value and calculated shift values, we can exclude the AW3 isomer because the combination value will be too high.…”

“…So we have recorded spectra from 80 to 6000 cm -1 of (AN) n -(H 2 O) m complexes, noted n:m (n and m equal to 1 or 2) isolated in solid neon at 3 K. Harmonic ab initio calculations are also undertaken to support our observations. We have shown in the past that it is possible to obtain new vibrational data in solid neon for hydrogen bonding complexes as H 2 S-H 2 O, methylamine-H 2 O, and methyl formate-H 2 O [13][14][15], the works in which we prove the existence of some complexes and give the geometries of theirs isomers.…”

Microhydration of Tertiary Amines: Robust Resonances in Red-Shifted Water

“…Its intensity strongly exceeds expectation for an infrared overtone, as indicated by the tiny bend overtone signals of the water monomer (M) that is present in large excess. This points to a resonance situation in which the OHb mode shares some of its infrared intensity due to wave function mixing . The associated coupling constant is denoted W 2 .…”