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Inferring molecular orientations from vibrational sum frequency generation (SFG) spectra is challenging in polarization combinations that result in low signal intensities, or when the local point group symmetry approximation fails. While combining experiments with density functional theory (DFT) could overcome this problem, the scope of the combined method has yet to be established. Here, we assess its feasibility of determining the distributions of molecular orientations for one monobasic ester, two epoxides and three alcohols at the vapor/fused silica interface. We find that molecular orientations of nonlocal vibrational modes cannot be determined using polarization-resolved SFG measurements alone. [ABSTRACT FROM AUTHOR]

Temporal system-mass-density fluctuation analysis was performed on liquid−water molecular-dynamics simulations at ambient pressure and 200 and 300 K, in three increasingly-large systems. A prominent mode in system-density fluctuations was observed at molecular-librational frequencies of ∼600−800 cm −1 (with pronounced temperature dependence). This mode displayed marked system-size dependence, disappearing for larger systems. Persistent system-density fluctuations were clearly evident at 10−11 cm −1 for all systems and temperatures, with lower-amplitude ‘overtones’ evident only in larger systems. It is conjectured that this reflects ∼3 ps timescales observed in earlier studies for dissipation of local-density fluctuations in liquid water in this 200−300 K temperature range. [ABSTRACT FROM AUTHOR]

• [P 1111 ][Gly] and [P 4444 ][Gly] were analyzed for CO 2 absorption capacity. • Reaction mechanism for CO 2 absorption was unveiled using DFT. • MD simulation used to understand the physical properties of ionic liquids. • Effect of water on ionic strength was also evaluated. Carbon dioxide is a well-known greenhouse gas that cause global warming. CO 2 capture and sequestration strategy is known promising strategy to reduce the level of CO 2 in the atmosphere. Thus, the usage of Amino Acid Ionic Liquids have gained attention for reversible CO 2 capture. Herein, we use DFT to report the effect of CO 2 chemisorption on tetramethylphosphonium glycinate and tetrabutylphosphonium glycinate ILs. Finally, Molecular Dynamics (MD) simulations were carried out to study the physicochemical properties of ILs in pure form and in the presence of explicit water. Overall, our study confirms the usage of studied ILs to efficiently capture CO 2. [ABSTRACT FROM AUTHOR]