The group has recently been investigating non-collinear two-component methods and two new publications in this area are now online. This is an exciting direction for the group that allows us to model phenomena that is impossible to capture with collinear methods such as restricted and unrestricted Hartree-Fock and DFT.
One paper focuses on the linear response of a two-component Hartree-Fock (2cHF) wave function. The 2cHF method retains proper degeneracy in the studied systems that are artificially broken with unrestricted HF. Both the real and complex cases were studied as well as the CIS approximation to the linear response.
The other paper builds off of previous work on two-component spin dynamics and by allowing the nuclei to evolve in time along with the electronic degrees of freedom. Two-component Ehrenfest is able to properly describe nuclear dynamics in regions of the potentially energy surface where different spin states are close in energy and spin symmetry is broken.
These papers are both published in the Journal of Chemical Physics. The linear response paper can be found here and the two-component Ehrenfest paper is available here.