dc.contributor.advisor | Ackland, Graeme | en |
dc.contributor.author | Cipcigan, Flaviu Serban | en |
dc.date.accessioned | 2018-03-15T11:53:17Z | |
dc.date.available | 2018-03-15T11:53:17Z | |
dc.date.issued | 2017-07-10 | |
dc.identifier.uri | http://hdl.handle.net/1842/28814 | |
dc.description.abstract | Electronic coarse graining is a technique improving the predictive power of molecular
dynamics simulations by representing electrons via a quantum harmonic
oscillator. This construction, known as a Quantum Drude Oscillator, provides
all molecular long-range responses by uniting many-body dispersion, polarisation
and cross interactions to all orders.
To demonstrate the predictive power of electronic coarse graining and provide
insights into the physics of water, a molecular model of water based on Quantum
Drude Oscillators is developed. The model is parametrised to the properties of
an isolated molecule and a single cut through the dimer energy surface. Such a
parametrisation makes the condensed phase properties of the model a prediction
rather than a fitting target. These properties are studied in four environments via
two-temperature adiabatic path integral molecular dynamics: a proton ordered
ice, the liquid{vapour interface, supercritical and supercooled water.
In all these environments, the model predicts a condensed phase in excellent
agreement with experiment, showing impressive transferability. It predicts correct
densities and pressures in liquid water from 220 K to 647 K, and a correct
temperature of maximum density. Furthermore, it predicts the surface tension,
the liquid-vapour critical point, density of ice II, and radial distribution functions
across all conditions studied.
The model also provides insight into the relationship between the molecular
structure of water and its condensed phase properties. An asymmetry between
donor and acceptor hydrogen bonds is identified as the molecular scale mechanism
responsible for the surface orientation of water molecules. The dipole moment
is identified as a molecular scale signature of liquid-like and gas-like regions in
supercritical water. Finally, a link between the coordination number and the
anomalous thermal expansion of the second coordination shell is also presented. | en |
dc.contributor.sponsor | Engineering and Physical Sciences Research Council (EPSRC) | en |
dc.language.iso | en | |
dc.publisher | The University of Edinburgh | en |
dc.relation.hasversion | Flaviu S. Cipcigan, Vlad P. Sokhan, Andrew P. Jones, Jason Crain, and Glenn J. Martyna. Hydrogen bonding and molecular orientation at the liquid{vapour interface of water. Phys. Chem. Chem. Phys., 17(14):8660{ 8669, 2015. doi: 10.1039/c4cp05506c. | en |
dc.relation.hasversion | Flaviu S. Cipcigan, Vlad P. Sokhan, Jason Crain, and Glenn J. Martyna. Electronic coarse graining enhances the predictive power of molecular simulation allowing challenges in water physics to be addressed. J. Comput. Phys., 326:222{233, 2016. doi: 10.1016/j.jcp.2016.08.030. | en |
dc.relation.hasversion | A. Jones, F. Cipcigan, V. P. Sokhan, J. Crain, and G. J. Martyna. Electronically coarse-grained model for water. Phys. Rev. Lett., 110(22), 2013. doi: 10.1103/physrevlett.110.227801. | en |
dc.relation.hasversion | A. P. Jones, J. Crain, F. S. Cipcigan, V. P. Sokhan, M. Modani, and G. J. Martyna. Electronically coarse-grained molecular dynamics using quantum drude oscillators. Mol. Phys., 111(22-23):3465{3477, 2013. doi: 10.1080/ 00268976.2013.843032. | en |
dc.relation.hasversion | V. P. Sokhan, A. Jones, F. S. Cipcigan, J. Crain, and G. J. Martyna. Molecular-scale remnants of the liquid-gas transition in supercritical polar uids. Phys. Rev. Lett., 115(11), 2015. doi: 10.1103/physrevlett.115.117801. | en |
dc.relation.hasversion | Vlad P. Sokhan, Andrew P. Jones, Flaviu S. Cipcigan, Jason Crain, and Glenn J. Martyna. Signature properties of water: Their molecular electronic origins. Proc. Natl. Acad. Sci. U.S.A., 112(20):6431{6346, 2015. doi: 10. 1073/pnas.1418982112. | en |
dc.subject | transferable water model | en |
dc.subject | coarse grained model | en |
dc.subject | supercooled water | en |
dc.subject | supercritical water | en |
dc.subject | ice II | en |
dc.subject | hydrogen bonding | en |
dc.subject | liquid-vapour interface | en |
dc.subject | molecular dynamics | en |
dc.subject | water | en |
dc.subject | path integral | en |
dc.title | Electronically coarse grained molecular model of water | en |
dc.type | Thesis or Dissertation | en |
dc.type.qualificationlevel | Doctoral | en |
dc.type.qualificationname | PhD Doctor of Philosophy | en |
dc.rights.embargodate | 2018-07-10 | |
dcterms.accessRights | Restricted Access | en |