On the solvation model and infrared spectroscopy of liquid water

Optimized infrared spectrum of ( H 2 O ) m : ( H C N ) n mixtures

Using density functional theory at D3-B3LYP/aug-cc-pVDZ level combined with the conductor-like polarizable continuum model (CPCM) solvent model, a study of the IR spectrum ofH 2 O :HCN mixtures is reported. The CPCM solvent effect notably enhances the accuracy of the IR spectra compared to gas-phase calculations, while the dielectric constant value has minimum impact on the final spectrum. An optimized methodology is suggested that effectively minimizes the root mean square deviation between theoretical and experimental data. This novel approach not only enhances the quality of the final IR spectra but also captures relevant spectral features, highlighting its potential to decipher molecular interactions in such intricate mixtures.

Effect of (H2O) n (n = 0-3, 13) on the NH3 + OH reaction in the gas and liquid phases

We studied the effect of water clusters on the NH3 + OH reaction at both the DFT and CCSD(T) levels. The calculated rate constants for the pure reaction are 2.07 × 10-13 and 1.35 × 10-13 cm3 molecule-1 s-1 in the gas and liquid phases, respectively, and the gas-phase rate constants are consistent with the corresponding experimental result (1.70 × 10-13 cm3 molecule-1 s-1), while the liquid-phase rate constants are slightly smaller than the experimental value (5.84 × 10-12 cm3 molecule-1 s-1). In the gas phase, the presence of (H2O) n (n = 1-3) decreases the rate constant compared to the pure NH3 + OH reaction, and these results are in agreement with many reported H2O-catalyzed reactions. For the liquid phase reaction, compared with the case of n = 0-3, when the size of the water molecule cluster surrounding the OH radical is n = 13, the rate constant of the title reaction increases. Our study also shows that proton transfer is also a factor which accelerates the liquid phase NH3 + OH reaction.