Application of the SCC-DFTB method to H+(H2O)6, H+(H2O)21, and H+(H2O)22.
The low-lying potential energy minima of the H(+)(H(2)O)(n), n = 6, 21, and 22, protonated water clusters have been investigated using two versions of the self-consistent-charge density-functional tight-binding plus dispersion (SCC-DFTB+D) electronic structure methods. The relative energies of different isomers calculated using the SCC-DFTB+D methods are compared with the results of DFT and MP2 calculations. This comparison reveals that for H(+)(H(2)O)(6) the SCC-DFTB+D method with H-bonding and third-order corrections more closely reproduces the results of the MP2 calculations, whereas for the n = 21 and 22 clusters, the uncorrected SCC-DFTB+D method performs better. Both versions of the SCC-DFTB+D method are found to be biased toward Zundel structures.
Choi
Tae Hoon
TH
Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Jordan
Kenneth D
KD
D006860:Hydrogen Bonding; D009010:Monte Carlo Method; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D014867:Water