Effective application of SCCDFTB in simulating structural and thermodynamic
properties of molecular systems

Hao Hu, haohu@duke.edu1, Weitao Yang, weitao.yang@duke.edu1, and Jan Hermans,
hermans@med.unc.edu2. (1) Department of Chemistry, Duke University, Box 90349,
Durham, NC 27708, (2) Department of Biochemistry and Biophysics, University of
North Carolina, Chapel Hill, NC 27599-7260

Designed to mimic ab initio Density Functional Theory, SCCDFTB reproduces very
well structural and energetic properties for a large variety of
molecules. Compared with many other semi-empirical QM methods, SCCDFTB produces
qualitatively better results with a comparable minimal computational cost. For
those reasons, the applications of SCCDFTB in the full-scale QM or combined
QM/MM simulations are very promising. We discuss here applications of SCCDFTB in
the calculation of structural and thermodynamic properties of different
molecular systems, specifically, full-scale QM simulation and accurate QM/MM
free energy simulation with SCCDFTB method. We will present the simulation
results of liquid water by linear-scaling divide-and-conquer SCCDFTB method,
with the comparison to classical water models. We will also show here how to
effectively implement SCCDFTB in free energy simulations, and discuss how to
combine SCCDFTB with high-level QM methods to achieve high-accuracy QM/MM free
energy simulations.