jp507752e_si_001.pdf (3.31 MB)
The Role of Quantum Effects on Structural and Electronic Fluctuations in Neat and Charged Water
journal contribution
posted on 2014-11-20, 00:00 authored by Federico Giberti, Ali A. Hassanali, Michele Ceriotti, Michele ParrinelloIn
this work, we revisit the role of nuclear quantum effects on
the structural and electronic properties of the excess proton in bulk
liquid water using advanced molecular dynamics techniques. The hydronium
ion is known to be a weak acceptor of a hydrogen bond which gives
it some hydrophobic character. Quantum effects reduce the degree of
this hydrophobicity which facilitates the fluctuations of the protons
along the wires compared to the classical proton. Although the Eigen
and Zundel species still appear to be dominant motifs, quantum fluctuations result in rather drastic events where both
transient autoionization and delocalization over extended proton wires
can simultaneously occur. These wild fluctuations also result in a
significant change of the electronic properties of the system such
as the broadening of the electronic density of states. An analysis
of the Wannier functions indicate that quantum fluctuations of neat
water molecules result in transient charging with subtle similarities
and differences to that of the excess proton.