Christopher D Daub

Learn More
We apply molecular dynamics (MD) simulations to study the final phase of electrospray ionization (ESI), where an ion loses all of its associated solvent molecules. By applying an electric field to a cluster of H(2)O molecules solvating an ion and including a surrounding gas of varying pressure, we demonstrate that collisions with the gas play a major role(More)
We examine the effect of nanoscale roughness on spreading and surface mobility of water nanodroplets. Using molecular dynamics, we consider model surfaces with sub-nanoscale asperities at varied surface coverage and with different distribution patterns. We test materials that are hydrophobic, and those that are hydrophilic in the absence of surface(More)
Applying an electric field is a well-established experimental method to tune surface wettability. As accessible experimental length scales become shorter, the modification of interfacial properties of water using electric field must come to grips with novel effects existing at the nanoscale. We survey recent progress in understanding these effects on water(More)
We study small clusters of water or methanol containing a single Ca(2+), Na(+), or Cl(-) ion with classical molecular dynamics simulations, using models that incorporate polarizability via the Drude oscillator framework. Evaporation and condensation of solvent from these clusters is examined in two systems, (1) for isolated clusters initially prepared at(More)
We manifest a significant influence of field direction and polarity on surface wetting, when the latter is tuned by application of an external electric field. Thermodynamics of field-induced filling of hydrocarbon-like nanopores with water is studied by open ensemble molecular simulation. Increased field strength consistently results in water-filling and(More)
We use molecular dynamics simulations in applied thermal gradients to study thermomolecular orientation (TMO) of size-asymmetric dipolar dumbbells with different molecular dipole moments. We find that the direction of the TMO is the same as in apolar dumbbells of the same size, i.e. the smaller atom in the dumbbell tends to orient towards the colder(More)
We study the behavior of ambient temperature water under the combined effects of nanoscale confinement and applied electric field. Using molecular simulations we analyze the thermodynamic causes of field-induced expansion at some conditions, and contraction at others. Repulsion among parallel water dipoles and mild weakening of interactions between(More)
We use atomistic simulations to study the orientational dynamics of a nonpolar nanoparticle suspended in water and subject to an electric field. Because of the molecular-level effects we describe, the torque exerted on the nanoparticle exceeds continuum-electrostatics-based estimates by about a factor of 2. The reorientation time of a 16.2 x 16.2 x 3.35(More)
Interfacial polar molecules feature a strongly anisotropic response to applied electric field, favoring dipole orientations parallel to the interface. In water, in particular, this effect combines with generic orientational preferences induced by spatial asymmetry of water hydrogen bonding under confined geometry, which may give rise to a Janus interface.(More)
We studied monosodium glutamate (MSG) in aqueous solution using molecular dynamics simulations and compared the results with recent neutron diffraction with isotope contrast variation/empirical potential structure refinement (EPSR) data obtained on the same system (McLain et al. J. Phys. Chem. B 2006, 110, 21251-21258). We used classical simulations with(More)