Infrared Spectra of Methanol and Deuterated Methanols in Gas, Liquid, and Solid Phases

Abstract

The infrared spectra of CH3OH, CH3OD, CD3OH, and CD3OD in the five phases gas, liquid, vitreous solid, α-crystal, and (except perhaps for CD3OH and CD3OD for which the solid-solid transitions have not been studied) β-crystal have been recorded in the range 4000 to 300 cm−1. The Raman spectrum of liquid CD3OH has been recorded. A complete assignment of the internal modes is given, which differs somewhat from previous assignments for the CH3 bending and rocking vibrations. No significant difference in spectrum occurred between the α-crystal and β-crystal phases. Under the full symmetry of the β-phase determined by x-ray diffraction only one OH out-of-plane bending band should occur. Two bands are observed, and it is concluded that the carbon and oxygen atoms in one chain are not coplanar, as is required by the symmetry determined by x-ray diffraction [K. J. Tauer and W. N. Lipscomb, Acta Cryst. 5, 606 (1952)], but that the chains are puckered and the x-ray symmetry arises because the puckered chains are irregularly distributed, a structure that had been previously suggested by Tauer and Lipscomb tentatively on the basis of high apparent thermal amplitudes. Bands occur in the crystal spectra near 500 cm−1 and 340 cm−1 at −180°C. These are interpreted as lattice modes, probably the two infrared-active modes that involve translations of the molecules.

Temperature, composition, and hydrogen isotope effect in the hydrogenation of CO on amorphous ice surface at 10–20K

“…These peaks are assigned to the D 2 CO vibration mode of CD 2 wagging, CD 2 scissoring, CO stretching, CD stretching, and CD 2 scissoring over tone, 24 respectively. As the exposure time increases, additional new peaks appear at 977, 1067, 1126, 2078, 2250, and 2430-2450 cm −1 ͑broad peak͒, corresponding to the CD 3 OD vibration mode of CO stretching, CD 3 asymmetry bending, CD 3 symmetry bending, CD 3 symmetry stretching, CD 3 asymmetry stretching, and OD stretching, 25 respectively. Although CD 3 OD has one more CD 3 asymmetry stretching mode at around 2217 cm −1 , we cannot distinguish that from the broad peak of the CD 2 scissoring overtone ͑2212 cm −1 ͒ in D 2 CO.…”

Simulating Energy Relaxation in Pump–Probe Vibrational Spectroscopy of Hydrogen-Bonded Liquids

“…The vibrational spectra computed here are in good agreement with those obtained by Car-Parrinello simulations 39 as well as with experiments. 40 The colored noise contribution of the thermostat was characterized by T max = 400 K, 1/γ peak = 0.5 ps and ∆ω = 1 cm −1 , while the white noise Langevin part was characterized by T base = 300 K and 1/γ base = 0.5 ps. Although the excitation is tuned with a narrow width, the response of the mode is broader and a small but noticeable effect on lower frequency modes can be observed (see Relaxation time The relaxation is monitored in 50 ps long NVE runs, during which atomic velocities are sampled to compute the kinetic temperature of different atomic species and the vDOS.…”

Competition between vitrification and crystallization of methanol at high pressure

“…Slower freezing from the liquid state yields an orthorhombic 18 crystalline ␤ phase at higher temperature ͑157 KрTр175 K͒. A crystalline ␣ phase is formed at lower temperature, 14,15 that is probably monoclinic. 18 Applying pressure to methanol at room temperature leads, according to the general notion in the literature, 19 to formation of a glass around 8.6 GPa.…”