jp0c02221_si_001.pdf (2.82 MB)
Solvation Shell of the Nitrite Ion in Water: An Ab Initio Molecular Dynamics Study
journal contribution
posted on 2020-08-05, 16:43 authored by Sushma Yadav, Amalendu ChandraWe performed ab initio molecular
dynamics simulation of a nitrite
ion in water to investigate the structural and dynamical properties
of its hydration shell. The nitrite ion is found to exhibit strong
asymmetry toward hydrogen bonding due to its two different types of
hydrogen bond acceptor sites. This difference is better captured through
further partitioning of the hydration shell into its proximal and
distal regions. The frequency shifts of the stretch modes of hydration
shell water reveal that the nitrogen site forms a stronger hydrogen
bond than its oxygen sites with the latter forming hydrogen bonds,
which are similar in strength to that between a pair of water molecules.
The escape dynamics of water from the hydration shell is found to
be rather slow, which seems to classify the nitrite ion as a structure-maker.
However, the dynamics of orientational and hydrogen bond relaxation
reveal a faster mobility of water molecules in the hydration shell
than bulk water in spite of strong ion–water interactions.
It is found that the nitrite ion can hold water molecules in its solvation
shell and still make them rotate fast in its vicinity through switching
of their hydrogen bonds between its nitrogen and oxygen acceptor sites.
The dipole moment of the solute in water is also calculated in the
present study.