Structural changes in the water tetramer. A combined Monte Carlo and DFT study

Abstract

The heat capacity curve of the water tetramer has been calculated at various levels of theory and over a broad range of temperatures, T = 50-200 K. Parallel-tempering and multiple-histogram Monte Carlo methods have been used and combined with the Density Functional Theory calculations of intra-cluster interactions via the Boltzmann-reweighting approach. It is demonstrated that such a combination can yield well converged thermodynamic data even for a modest number of sample configurations, which makes the methodology particularly appropriate for the inclusion of quantum chemistry calculations in Monte Carlo simulations. The B97-1 exchange-correlation functional has been used in the present work together with augmented correlation-consistent basis sets of atomic orbitals up to triple-zeta quality. A structural change has been detected in the water tetramer in the temperature range considered. It is demonstrated that the change corresponds to the onset of rotations of the water molecules around hydrogen bonds with an almost rigid skeleton of the cluster (square cycle) conserved.

A Computational Validation of Water Molecules Adsorption on an NaCl Surface

“…A new STM report by Jiang et al observed twodimensional ice on an Au(111) surface [15]. Also, we simulated the adsorption of water Vitek et al calculated the geometry structure of water tetramer [17]. Besides the four linked hydrogen bonds' inner four-molecule ring, the arrangement of the four dangling hydrogens is up-down-up-down with respect to the planar square cycle.…”

“…Vitek et al calculated the geometry structure of water tetramer [17]. Besides the four linked hydrogen bonds' inner four-molecule ring, the arrangement of the four dangling hydrogens is up-down-up-down with respect to the planar square cycle.…”

Thermodynamics of water clusters under high pressures. A case study for (H2O)15 and (H2O)15CH4

“…Both the temperatures and pressures have been spaced non-uniformly along the temperature or pressure axes. Following an earlier study, 19 the exponential increase of spacings is used for temperatures with the spacing between the two largest temperatures being 15 times larger than the spacing between the two lowest temperatures. For pressures, approximately exponential increase of spacings has also been used, but disturbed by adding a few additional pressures in the region where a phase change has been detected between lowpressure and high-pressure solid forms of [H 2 O] 15 and [H 2 O] 15 CH 4 (see Section 3).…”

A thermodynamic view on the microsolvation of ions by rare gas: application to Li+ with argon

“…These problems are minimized with the use of extended ensemble techniques, such as parallel tempering Monte Carlo (PTMC), which uses several replicas at different temperatures to build a new ensemble where attempts to exchange between replicas at different temperatures are performed. Although PTMC methodology has been applied to study several atomic and molecular clusters [14][15][16][17][18][19][20][21][22][23][24][25] , to the best of our knowledge, its use with microsolvation systems is very scarce and limited to model solvents 26,27 .…”