16th Students' Congress of SCTM

Theory of THz spectroscopy of liquid water

Not scheduled

20m

Amphitheatre (Faculty of Technology and Metallurgy, Skopje )

Speaker

Mr Dimitar Apoleski (Institute of Chemistry, Faculty of Natural Sciences and Mathematics, SS Cyril and Methodius University, 1000 Skopje, Republic of North Macedonia)

Description

A combined molecular dynamics – quantum mechanical model was developed, aiming at understanding of the THz spectroscopy of bulk liquid water. Classical molecular dynamics simulations, based on many-body interaction potentials derived specifically for water, were used to generate snapshots which were further subjected to quantum mechanical DFT calculations.
Selected clusters from 100 MD snapshots were chosen such as to include: i) all the water molecules from the first hydration shell around randomly chosen water molecules, embedded in bulk water treated as a polarizable continuum; ii) all the water molecules from the first and second hydration shells around randomly chosen water molecules, embedded in bulk water treated as a polarizable continuum; iii) series of clusters involving sequentially increasing number of water molecules around randomly chosen one, embedded in a polarizable continuum. Partial geometry optimizations for all mentioned clusters were performed, fixing different regions of the shell structure, followed by computation of the second derivative matrices and harmonic vibrational frequencies at HCTH/aug-cc-pVTZ level of theory.
Excellent agreement was obtained between the results generated from the developed theoretical model and the experimental THz spectroscopic data.

Keywords: water, THz spectroscopy, DFT, molecular dynamics.