Abstract

I will describe an ab initio-based potential energy surface (PES) for the hydrated proton using a many-body approach, obtained from fitting tens of thousands of CCSD electronic energies for the various components of the potential. A similar approach for the dipole moment surface will also be briefly described. The talk will a general presentation describing “non-parametric” fitting strategies using permutationally invariant polynomials (PIPs). Some results from a recent paper [J. Chem. Theory Comput. 2018, 14, 3381−3396] will be given describing Gaussian process regression using PIP as inputs.

Quantum VSCF /VCI calculations of the IR spectra of several H+(H2O)n cold clusters and comparisons with experiment will be given with a focus on the “Eigen/Zundel controversy”. Time permitting, very recent work assessing the accuracy of “TRPMD” for several spectra will be given as well as new VSCF /VCI calculations of the room temperature aqueous spectrum of the hydrated proton reported by the Tokmakoff group.