Cold molecules are a versatile tool for a wide range of applications. Cold molecules have been identified as attractive systems for quantum information processing and ultra-high resolution spectroscopy with the aim of developing new time standards and testing fundamental physical theories such as the time variation of physical constants, the existence of a dipole moment of the electron or the measurement of parity violation. A particularly interesting field is ultra-cold chemistry which investigates quantum mechanical effects in chemical reactions. The large thermal de Broglie wavelengths of molecules at very low temperatures profoundly influence chemical dynamics. At low energies these are dominated by severe constraints on the orbital angular momentum of collisions, the occurrence of reactive resonances and tunneling, and a pronounced dependence of the cross section on the collision energy. These effects are averaged out at higher temperatures.
In contrast to atoms molecules have a very complicated level structure that consists of electronic levels as well as vibrational and rotational states. This abundance of states makes coherent control of internal states difficult and is the main obstacle for direct laser cooling of molecules. Most importantly, molecules do not provide the closed transitions required for cooling and non-destructive state-selective detection. This makes it impossible to perform direct spectroscopic measurements on single molecules which is a standard technique in atomic physics.
The aim of the Sussex Molecular Physics Lab is to develop tools to identify molecular ions, detect and cool they internal states and to employ these tool to perform high resolution spectroscopy and to investigate ultra-cold chemical reaction (Collaboration with Softley Group, Oxford.)