Systematic Characterization of Gas Phase Binary Pre-Nucleation Complexes Containing HSO + X, [ X = NH, (CH)NH, (CH)NH, (CH)N, HO, (CH)OH, (CH)O, HF, CHF, PH, (CH)PH, (CH)PH, (CH)P, HS, (CH)SH, (CH)S, HCl, (CH)Cl)]. A Computational Study.

A systematic characterization of gas phase binary prenucleation complexes between HSO (SA) and other molecules present in the atmosphere (NH, (CH)NH, (CH)NH, (CH)N, HO, (CH)OH, (CH)O, HF, CH F, PH, (CH)PH, (CH)PH, (CH)P, HS, (CH)SH, (CH)S, HCl, (CH)Cl) has been carried out using the ωB97X-D/6-311++(2d,2p) method at the DFT level of theory. A relationship between the energy gap of the SA's LUMO and the partner molecule's HOMO, and the increasing number of methyl groups -CH in the SA's partner molecule is provided. The binding energies of the bimolecular complexes are found to be related to the electron density in the hydrogen bond critical point, the HOMO-LUMO energy gap, the nature of the hydrogen acceptor atom, and the frequencies shift of acid OH bonds.

The water supercooled regime as described by four common water models.

The temperature scale of simple water models in general does not coincide with the natural one. Therefore, in order to make a meaningful evaluation of different water models, a temperature rescaling is necessary. In this paper, we introduce a rescaling using the melting temperature and the temperature corresponding to the maximum of the heat capacity to evaluate four common water models (TIP4P-Ew, TIP4P-2005, TIP5P-Ew and Six-Sites) in the supercooled regime.

Temperature dependence of ice critical nucleus size.

We present a molecular dynamics study of ice growth from supercooled water. By performing a series of simulations with different initial conditions, we have quantitative established the relationship existing between the critical nucleus size and the temperature. The results show that ice embryos containing hundreds or thousands of molecules are needed for the system to crystallize macroscopically, even at high degrees of supercooling.