Solvation and Embedding Methods in Q-Chem


EFP can be used to compute ionization energies and redox potentials of solvated species
QM/MM double-stranded DNA
HOMO and LUMO of a Watson-Crick base pair in a QM/MM description of double-stranded DNA

Q-Chem offers many methods for treating complex systems such as molecules in solutions, proteins, polymers, molecular clusters, etc.


  • Implicit solvation models

    • SM8, SM12, SMD, COSMO, C-PCM,  SS(V)PE, IEF-PCM, CMIRS, and more

    • Intrinsically smooth discretization of the solute/continuum interface

    • Poisson equation solver for anisotropic dielectric boundary conditions


  • Effective fragment potential (EFP) for modeling explicit solvent with polarizable embedding

    • Built-in library of effective fragments and user-defined potentials

    • Available for DFT and wave function-based ground and excited state methods

    • Fragmented EFP scheme for macromolecules


  • Stand-alone QM/MM capabilities

    • Available for ground- or excited-state QM treatments

    • “Yin-Yang atom” approach to  defining the QM/MM boundary

    • Integration with PCM models (QC/MM/PCM)

    • Many-body expansion for incorporating solvent at a QM level


  • Interface to CHARMM and GROMACS


  • Density embedding methods

    • Projected-based density embedding for DFT-in-DFT or WFT-in-DFT

    • Frozen-Density embedding (FDE)  and polarizable embedding (PE via EFP) for Algebraic Diagrammatic Construction (ADC) scheme