Abstract
Accurate descriptions of many-particle quantum systems subject to laser interactions can be found using real-time ab initio methods. Of these the arguably most popular and exact is the multi-configuration time-dependent Hartree-Fock (MCTDHF) method. However, MCTDHF suffers from computational limitations in that it quickly becomes too time consuming. The orbital-adaptive time-dependent coupled-cluster (OATDCC) method represents a hierarchy of approximations to MCTDHF that are less computationally expensive while retaining as much accuracy as possible. Building on an existing codebase we have in this thesis generalized the OATDCC method to include Q-space orbital equations. A novel ground state solver is implemented, employing adiabatic switching, since imaginary time propagation is not feasible "out of the box". Furthermore, we implement a sinc-discrete variable representation basis for one-dimensional model systems. We demonstrate that ionization and high-harmonic processes can be described using the OATDCCD method. Comparison with the more accurate, yet more expensive, multiconfigurational time-dependent Hartree-Fock method indicates that the OATDCCD method is an excellent approximation.