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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 44: Charged Soft Matter I

CPP 44.11: Vortrag

Donnerstag, 3. April 2014, 12:15–12:30, ZEU 118

Modelling of neutron spectroscopy of hydrogen bonded organic crystals using first principles density functional theory — •Sanghamitra Mukhopadhyay — ISIS Facility, Rutherford Appleton Loboratory - STFC, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX

Hydrogen bonded organic crystals are important both for fundamental chemical interests as well as for technological applications. Neutron spectroscopy is used to understand these hydrogen bonded materials experimentally. The static lattice dynamics are not often suitable to analyse these spectroscopic results, specially, where complex picosecond order dynamics are involved. In this work we will present our work on modelling of neutron spectroscopic results using first principles lattice and molecular dynamics.

We employed state-of-the-art calculations based on plane wave pseudo potential density functional theory to predict the structure of croconic acid, an organic molecular crystal, showed room temperature ferroelectricity, and compared with in-house neutron diffraction and inelastic neutron scattering (INS) spectrum to understand the nature of hydrogen bonds in this material. The quasielastic spectrum were calculated by analysing the trajectory of the molecular dynamical simulations and also compared with experiments.

We will discuss the neutron spectrum in terms of motions of hydrogen ions. The calculated Born effective charge tensors are used to understand the nature of dynamic charges and the origin of ferroelectricity.