"A high pressure structure search for low-energy Chalcogens".

The Group VI Chalcogens have six valence electrons and form 2- ions. In this project, I will study S, Se, and Te structures under high-pressure conditions (approx. 50-500GPa); in the lower-half of this interval, these elements have been experimentally observed to be superconducting. I will use the "ab initio random structure searching" (AIRSS) method to determine the lowest energy structures of S, Se, and Te over this pressure range. I will also develop basic structure searching code for determining potential incommensurate phases of these elements, including S, Se, Te, and Po, by applying random modulations to an unmodulated average structure.

The Group VI Chalcogens, S, Se, Te and the radioactive element polonium Po have many uses, including semiconductors (O will be considered elsewhere). Plants and animals require S to process nutrients. Large amounts of S are used to vulcanize rubber and produce sulfuric and phosphoric acids, explosives, pesticides, fertilizers, and concrete. Se is used in producing glass and in metallurgy. Te is used in manufacturing computer disks, light sensors, solar panels, lubricants and petroleum products.