Attosecond Spin-Orbit Spectroscopy

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High Harmonic Spectroscopy (HHS) is a technique used to 'observe' extremely fast processes, such as the the motion of atoms within a molecule or electrons within an atom. HHS operates on the principle that when we shine a laser into a gas, different colours of light are emitted, and the characteristics of this colour spectrum reveal the underlying processes within the atoms or molecules that make up the gas.Recent developments have allowed HHS techniques to be used to investigate even more exotic processes such as so-called 'relativistic effects' which involve complex interactions between the electrons in an atom. In this PhD I will use computer simulations of HHS to investigate this area further; especially how the interplay between the particular laser pulse parameters and the relativistic effects influence the light emitted, and how this can be interpreted in terms of processes occurring within the atom.To do this, I will use the R-matrix with time-dependence (RMT) code. RMT runs on massively parallel (or 'super') computers and is designed to simulate the processes that occur within a single atom or molecule irradiated by a laser. Recent developments in the RMT code allow it to model processes beyond the reach of competing methods.The benefits of RMT simulations to the scientific community are that they can be used * to investigate atomic/molecular processes without the overhead costs of experimental setup and equipment, * to improve confidence in experimental results by replicating them, * to interpret the mechanisms causing particular experimental features, * to simulate processes beyond the current capabilities of real-world experiments. During the course of this PhD I will enhance these benefits through my secondary aim of extending and improving the RMT code. This will allow ever more complex effects to be described, as well as improving the efficiency with which meaningful results may be generated.