College of Chem. & Mol. Engineering Prof. Liu, a Cheung Kong Scholar since 2001, has been developing relativistic quantum mechanical theories and methods for the chemistry and physics of systems containing heavy elements, including several relativistic many-electron Hamiltonians (effective QED, Q4C, X2C, and sf-X2C+sd-DKHn), several variants of 4C/X2C NMR/NSR theories, relativistic/spin-adapted open-shell/linear-scaling TD-DFT, as well as a general framework for relativistic explicitly correlated methods.

Currently his group is developing new wavefunction-based methods for strongly correlated electrons under the scenario of "first dynamic then static", fragment-based low-order scaling non-relativistic and relativistic explicitly correlated methods, as well as solid state NMR. The in-house BDF (Beijing Density Functional) suit of program packages serves as the platform for the developments.