Calculations of Mode-Specific Tunneling of Double-Hydrogen Transfer in Porphycene Agree with and Illuminate Experiment.
We report a theoretical study of mode-specific tunneling splittings in double-hydrogen transfer in trans-porphycene. We use a novel, mode-specific "Qim path method", in which the reaction coordinate is the imaginary-frequency normal mode of the saddle point separating the equivalent minima. The model considers all 108 normal modes and uses no adjustable parameters. The method gives the ground vibrational-state tunneling splitting, as well the increase in the splitting upon excitation of certain modes, in good agreement with experiment. Interpretation of these results is also transparent with this method. In addition, predictions are made for mode excitations not investigated experimentally. Results for d1 and d2 isotopolgues are also in agreement with experiment.
Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
Zahra
Z
Homayoon
Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
Joel M
JM
Bowman
Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
Francesco A
FA
Evangelista
d1, d2 isotopolgues; double-hydrogen transfer; mode-specific tunneling; porphycene; projection model