Sökning: "Jonatan Öström"

Hittade 2 avhandlingar innehållade orden Jonatan Öström.

1. 1. A flexible and polarizable water model built on interpolated multipoles

   Författare :Jonatan Öström; Lars Gunnar Moody Pettersson; Gábor Csányi; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Multipole; Regression; Polarization; Machine Learning; Molecular Dynamics; Water; Theoretical Physics; teoretisk fysik;

   Sammanfattning : Water has a rich phase diagram with regions of meta-stability, the prime examples being super-cooled and super-heated liquid water.Below ca 50 °C, water exhibits unusual and not yet fully explained anomalous thermodynamic properties upon cooling, for example a minimum in compressibility at 46 °C, a minimum in heat capacity at 35 °C, a density maximum at 4 °C, and a compressibility maximum at -44 °C in the supercooled liquid, at ambient pressure. LÄS MER

3. 2. Development of a water model with arbitrary rank multipolar polarization, repulsion and electrostatics

   Författare :Jonatan Öström; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; teoretisk fysik; Theoretical Physics;

   Sammanfattning : I report on the derivation, development and computer implementation of methods for computing the energies and forces between small rigid polarizable molecules, that are defined by the center-of-mass moments of their electronic and nuclear charge distributions and their linear response moments. The formalism is based on compact and efficient storage and manipulation of symmetric Cartesian tensors of arbitrary rank, and a general formula for the Cartesian gradients of one-dimensional interaction (kernel) potentials. LÄS MER