The R-matrix with time dependence (RMT) suite of codes was originally developed to treat the interaction of atoms and molecules with linearly-polarized laser fields [1]. In this talk we present two major extensions of the RMT method — the ability to handle arbitrarily-polarized light fields, and the inclusion of spin-orbit interactions. These extensions incur an appreciable increase in computational demand compared to previous calculations, but allow access to significant new physics that is currently beyond the scope of other numerical methods. In this seminar, we will present the first results from these new developments. These include a proof-of-principle study [2] using the helium atom in circular fields, electron detachment from F$^-$ ion by circular fields. and a demonstration of spin-orbit mediated electron dynamics in atomic krypton. We will show that studies to date have shown good agreement with comparable numerical [3] and analytical methods [4], and we will discuss several exciting avenues for further research.

[1] L. R. Moore, M. A. Lysaght, L. A. A. Nikolopoulos, J. S. Parker, H. W. van der Hart and K. T. Taylor, J. Mod. Opt. 58 1132 (2011).

[2] D. D. A. Clarke, G. S. J. Armstrong, A. C. Brown, and H. W. van der Hart, Phys. Rev. A, accepted (2018).

[3] J. M. Ngoko Djiokap, A. V. Mermiannin, N. L. Manakov, S. X. Hu, L. B. Madsen and A. F. Starace, Phys. Rev. A 94 013408 (2016).

[4] I. Barth and O. Smirnova, Phys. Rev. A 84 063415 (2011).