Frozen water has a quasi-liquid layer at its surface that exists even well below the bulk
melting temperature; the formation of this layer is termed premelting. The nature of the …

Quantum crystals abound in the whole range of solid-state species. Below a certain
threshold temperature the physical behavior of rare gases (He 4 and Ne), molecular solids …

The electronic properties and optical response of ice and water are intricately shaped by
their molecular structure, including the quantum mechanical nature of the hydrogen atoms …

We review the use of continuum quantum Monte Carlo (QMC) methods for the calculation of
energy gaps from first principles, and present a broad set of excited-state calculations …

Helium diffraction has the potential to reveal the degree of proton order at an ice surface,
and has been used in the past to benchmark theoretical work. We demonstrate that previous …

In this report, the perovskite materials CsGeX 3 and CsGeX 2 X'(X and X'= Cl, Br, I) are
studied using density functional theory (DFT) and a time-dependent (TD)-DFT approach …

High-level vibrational calculations have been used to investigate anharmonicity in a wide
variety of materials using density functional theory methods. We have developed an efficient …

We study excited-state phenomena in a variety of semiconductor systems, with use of the
variational and diffusion quantum Monte Carlo (QMC) methods. Firstly, we consider the …

Photochemical oxidation of atmospheric elemental mercury (Hg0) promotes reactive
oxidized Hg (HgII) adsorption on particles and deposition to the polar snowpack. The …

Three-dimensionally resolved proton momentum distributions and end-to-end distributions
have been calculated for hexagonal and cubic water ice. First-principles quantum nuclear …