Meng Huang and Anne B. McCoy Department of Chemistry and Biochemistry The Ohio State Univerisity

Provide good model for studying the interactions between ions and molecules such as intramolecular hydrogen-bonding May provide explanations to important processes such as the transport of ions through membranes Important clusters in aqueous chemistry Assignment to the experimental spectrum taken by argon predissociation spectra [1] [1] Horvath. S., McCoy, A. B., Elliot, B. M.,Weddle, G. H., Roscioli, J. R., and Johnson, M. A., J. Phys. Chem. A, 114, 1556–1568 (2010).

Photon Energy, cm PeakPosition, cm -1 1 (2 oop ) ( HOH ) ( HOH + ip ) ( HOH + ip ) (2 HOH ) (2 HOH + OX ) ( OHb ) ( OHb ) ( OHb + OX ) ( OHb + OX ) ( OHf ) ( OHf ) [1] Horvath. S., McCoy, A. B., Elliot, B. M.,Weddle, G. H., Roscioli, J. R., and Johnson, M. A., J. Phys. Chem. A, 114, 1556–1568 (2010).

EquilibriumTransition State ip x y as s ipip =0 ip

Potential Energy Surface/Force Constants ab initio calculation with MP2/aug-cc-pVTZ-(PP) level of theory Dipole Moment/First order Dipole Derivative ab initio calculation with MP2/aug-cc-pVTZ-(PP) level of theory Basis Sets for Linear Variation Calculation Stretch Mode : Harmonic Oscillator In-plane Bend : Grid Basis Set (DVR) Simulation of Spectra Lorentzian (FWHM = 5 cm -1 )

ν OH b ν OH b + ν OX ν OH b + ν ip ν OH f 2ν HOH ν OH b ν OH f ν OH b + ν ip ν OD b ν OD b + ν ip ν OD f ν OD b 2ν DOD Combination Band ν OH b + ν ip

Normal Mode Frequencies of O-H Stretch Modes in I-(H 2 O) Potential energy surface and energy levels of the in-plane bending mode for I - (H 2 O) Tunneling Splitting

The increase of the barrier height leads to the overlap between ground state wavefunction and bending excited state. The tunneling splitting also decreases dramatically from ground state to excited state. ν OH b =1 ν OH b =0 ν ip =1 ν ip =0 ν OH b ν OH b + ν ip

Experimental Spectrum of X - (H 2 O)Calculated Spectrum of X - (H 2 O) ν OH b ν OH f ν OH b + ν ip 2ν HOH Cl - (H 2 O) Br - (H 2 O) I - (H 2 O) Br - (H 2 O) l - (H 2 O)

Experimental Spectrum of X - (D 2 O) Calculated Spectrum of X - (D 2 O) Cl - (D 2 O) Br - (D 2 O) I - (D 2 O) ν OD f ν OD b 2ν DOD ν OD b + ν ip

509 cm cm cm -1 The comparison among different calculated hydrated halide clusters spectra provides expected result.

Reduced dimensional analysis show qualitative agreement with the experimental spectrum Doublet structure in the O-H stretch transition is attributed to the double well potential in in-plane bending mode One transition is assigned to be combination band of O-H stretch and in - plane bending mode Comparison among calculated spectra of different hydrated halide clusters also show the expected result

Dr. Anne B. McCoy Andrew Petit Zhou Lin Bernice Opoku-Agyeman Laura Dzugan Bethany Wellen Jason Ford Thank you!