Isothermal crystallization of ternary (Ge,S,), -X(Sn,S,), glasses is examined over the glass forming range 0 < x < 0.6. Time-temperature-transformation (TIT) curves are obtained using scanning calorimetry. The results show that both nucleation and growth processes dominate crystallization of the glasses in the range 0 < .Y < 0.25, but only growth processes are found to occur once x 2 0.25. The ...

Recent reports have suggested that the nuclear resonant absorption of a long-lived Mossbauer state e.g., (93m)Nb is mediated by an entangled photon pair (biphoton) rather than by a single photon. Multipolar nuclear excitation in crystals of a single isotope with a natural abundance of 100% spreads in a region containing billions of identical nuclei. As a consequence of the delocalisation, addit...

Mdssbauer parameters are reported for the phosphate minerals triplite, zwieselite, triploidite, and wolfeite. Analysis of the absorption data confirms the existence of non-equivalent ferrous ions. The broadening of the resonance peaks is rationalized on the basis of a microscopic disorder due to half-occupied fluorine sites in the fluoride minerals and to sets of closelv related metal sites in ...

We develop a tight-binding model description of semi-Dirac electronic spectra, with highly anisotropic dispersion around point Fermi surfaces, recently discovered in electronic structure calculations of VO2-TiO2 nanoheterostructures. We contrast their spectral properties with the well-known Dirac points on the honeycomb lattice relevant to graphene layers and the spectra of bands touching each ...

We have applied a novel theoretical and computational method called CECILIA (combined embedded cluster at the interface with liquid approach) to study adsorption of molecular water on the MgO(001) surface and its interface with water. The MgO(001) surface is modeled by a quantum cluster embedded in a field of pseudopotentials and point charges. The effects of an aqueous environment are included...

The CP29 light harvesting complex from green plants is a pigment-protein complex believed to collect, conduct, and quench electronic excitation energy in photosynthesis. We have spectroscopically determined the relative angle between electronic transition dipole moments of its chlorophyll excitation energy transfer pairs in their local protein environments without relying on simulations or an X...

Coherence oscillations measured in two-dimensional (2D) electronic spectra of pigment-protein complexes may have electronic, vibrational, or mixed-character vibronic origins, which depend on the degree of electronic-vibrational mixing. Oscillations from intrapigment vibrations can obscure the inter-site coherence lifetime of interest in elucidating the mechanisms of energy transfer in photosynt...