An implementation of DFTB in amber9

Adrian E Roitberg, Department of Chemistry, University of Florida, Quantum
Theory Project, Gainesville, FL 32611

We will present details of the implementation of DFTB in amber 9.0, with
emphasis on the comparison with other semiempirical methods. We will also show
how DFTB and DFTB/D relative conformational energies for polyalanine peptides
compares with more traditional QM methods such as HF, DFT, MP2 and LMP2. The
correlation of DFTB/D results with MP2 and B3LYP/D will be shown to be
extremelly good. An example of applications of amber 9 QM/MM to enzymatic
systems will be exemplified for the enzyme transialidase.