Enhancement of the local asymmetry in the hydrogen bond network of liquid water by an ultrafast electric field pulse

Abstract

Condensed phase electron decomposition analysis based on density functional theory has recently revealed an asymmetry in the hydrogen-bond network in liquid water, in the sense that a significant population of water molecules are simultaneously donating and accepting one strong hydrogen-bond and another substantially weaker one. Here we investigate this asymmetry, as well as broader structural and energetic features of water’s hydrogen-bond network, following the application of an intense electric field square pulse that invokes the ultrafast reorientation of water molecules. We find that the necessary field-strength required to invoke an ultrafast alignment in a picosecond time window is on the order of 10 8 Vm −1 . The resulting orientational anisotropy imposes an experimentally measurable signature on the structure and dynamics of the hydrogen-bond network, including its asymmetry, which is strongly enhanced. The dependence of the molecular reorientation dynamics on the field-strength can be understood by relating the magnitude of the water dipole–field interaction to the rotational kinetic energy, as well as the hydrogen-bond energy.

Multidimensional insights into the repeated electromagnetic field stimulation and biosystems interaction in aging and age-related diseases

“…Of special note, this electrokinetic confined or trapped water exhibits a quantum tunneling behavior [ 115 ]. These data suggest that the interfacial water is a potential target for the effects of REMFS, which is confirmed by other investigators that proposed that water is a sensor for low energy EMF [ 116 ].…”

Tumbling with a limp: local asymmetry in water's hydrogen bond network and its consequences

“…The effect of an electric field on the local HB asymmetry in water was investigated with AIMD using an intense electric field square pulse with an intensity of 4.3 × 10 9 V m −1 . 61 The pulse strength was chosen such that it induces an ultrafast re-orientation of the water molecules on a sub-picosecond time scale. Under these conditions, it was shown that within 300 fs, the water molecules reach a steady-state average orientation angle of 37 degrees ( cos(θ ) ≈ 0.8), where the angle is calculated between the molecular bisector and the direction of the external field.…”

“…[10][11][12] In this article, we are going to review some of our efforts in unraveling a particular aspect of water's HB network, which is the local asymmetry in the strengths of HBs donated or accepted from/to a water molecule in bulk liquid water under ambient conditions. 9,13,14,21,40,43,48,61 While it is well known that the HB strength in water or in ice exhibit a broad distribution trivially due to thermal fluctuations, the novel and non-trivial aspect that was revealed is that in liquid water (but not in hexagonal ice), thermal motion leads to a significant population of molecules, where the strength of the two donor or acceptor interactions have an extreme disparity with as much as 25% of the molecules having one donor (acceptor) interaction that is more than six times stronger than the other donor (acceptor) interaction, and a significant pop-ulation having both kinds of interactions highly asymmetric. This interesting feature of water's HB network was revealed using ab initio molecular dynamics (AIMD) simulations ?…”

CP2K: An Electronic Structure and Molecular Dynamics Software Package -- Quickstep: Efficient and Accurate Electronic Structure Calculations

“…The superior efficiency of this method originates from the fact that only one preconditioned gradient computation is necessary per AIMD step. In fact, a gain in efficiency between one to two orders of magnitude has been observed for a large variety of different systems ranging from molecules and solids [238][239][240][241][242][243][244][245], including phase-change materials [246][247][248][249][250][251][252], over aqueous systems [253][254][255][256][257][258][259][260][261], to complex interfaces [262][263][264][265][266][267][268].…”

“…The ALMO EDA has been applied to study intermolecular interactions in a variety of gas-and condensed-phase molecular systems [288,290]. The CP2K implementation of ALMO EDA has been particularly advantageous to understand the nature of hydrogen bonding in bulk liquid water [208,214,216,255,258,259,261,289], ice [291] and water phases confined to low dimensions [292]. Multiple studies have pointed out a deep connection between the donor-acceptor interactions and features of the X-ray absorption [214,293], infrared (IR) [255,256,258,261,289,294,295] (Fig.…”