1. Zachary N. Vealey, Lidor Foguel, & Patrick H. Vaccaro
Proton Transfer and Low-Barrier Hydrogen Bonding: Shifting Vibrational Landscapes Dictated by Large Amplitude Tunneling
Zachary N. Vealey, Lidor Foguel, & Patrick H. Vaccaro
Department of Chemistry, Yale University
225 Prospect St., New Haven, CT USA

2. Proton Transfer and Tunneling
Deceptively simple migration of hydron between donor and acceptor sites
Tunneling Coordinate
Relative Intensity MA
Unimolecular transformation represents a prototypical chemical reaction
6-Hydroxy-2-Formylfulvene (HFF)
Model systems provide valuable insight for dynamics in much larger entities
TrOH
Tunneling-mediated pathways promoted by the small mass of labile proton
Proton-Transfer Rate:
Continuum of Hydrogen Bonding and Tunneling Dynamics
Low-Barrier Hydrogen Bond

3. Calculated Barriers and Structures
M06-2X/aug-cc-pVDZ
H or D
CCSD/aug-cc-pVDZ
Global
Minimum
Transition
State
CCSD/aug-cc-pVDZ

4. Experimental Setup

5. U.S. National Science Foundation
Summary & Conclusions ~
PROBED A1B2 LOWEST-LYING SINGLET ELECTRONIC STATE OF HFF
LIF spectra show extensive excited-state progressions of rxn-modulating modes
Small (~24°) out-of-plane distortion predicted for transition-state geometry
Rotational band-contour analyses reveal dramatic quenching of proton transfer
INTERROGATED X 1A1 GROUND ELECTRONIC STATE OF HFF
DF spectra reveal largest-ever reported vibrationless tunneling splitting
Large magnitude tunneling reflected in mode-specific dynamics
DKIE highlight continuum between tunneling and barrierless reaction dynamics ~
ONGOING AND FUTURE WORK
Deploy multiple resonance techniques (SEP & RFWM) to elucidate ground state
Investigate proton-transfer channels in neighboring electronic states of HFF
Explore dynamics in weakly bound complexes built on the HFF scaffold
WD02
Supported by:
U.S. National Science Foundation