By Shuhua Li
School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing, 210093, P. R. China

In this talk, I will present our recent advances in developing the generalized energy-based fragmentation approach for large molecules and molecules in condensed phases. The generalized energy-based fragmentation (GEBF) approach is a linear scaling technique that can extend ab initio calculations to very large systems. Within this approach, the ground-state energy of a large molecule can be evaluated directly from energies of various small “embedded” subsystems.1 The GEBF approach has been employed to investigate relative energies of different conformers, optimized structures, vibrational spectra for a wide variety of complex systems.2-5 Recently, the GEBF approach was extended to molecular crystals with periodic boundary conditions (PBC).6 In the PBC-GEBF approach, geometry optimizations6 and vibrational frequencies of molecular crystals7 have been implemented. Our applications demonstrate that the PBC-GEBF method with molecular quantum chemistry methods is capable of providing satisfactory descriptions on the lattice energies, structures, and vibrational spectra for various types of molecular crystals. By combining the PBC-GEBF approach and molecular dynamics simulations, we can now compute the radial distribution functions, vibration spectra (IR and Raman) for molecules in solution with full quantum mechanical calculations. 8 A direct comparison between the calculation results and related experimental results allows us to gain a deeper understanding of structures and spectra of molecules in condensed phases. 

References

1. W. Li, S. Li, Y. Jiang J. Phys. Chem. A 2007, 111, 2193.
2. W. Hua, T. Fang, W. Li, J.-G. Yu, and S. Li, J. Phys. Chem. A 2008, 112, 10864.
3. S. Hua; W. Hua, S. Li J. Phys. Chem. A 2010, 114, 8126.
4. S. Hua; W. Li, S. Li ChemPhysChem. 2013, 14, 108.
5. S. Li, W. Li, J. Ma, Acc. Chem. Res. 2014, 47, 2712.
6. T. Fang; W. Li; F. Gu; S. Li J. Chem. Theory Comput. 2015, 11, 91
7. T. Fang; S. Li, to be submitted, 2015
8. 8.    D. Yuan; S. Li, to be submitted, 2015