Calculations of Mode-Specific Tunneling of Double-Hydrogen Transfer in Porphycene Agree with and Illuminate Experiment
journal contributionposted on 17.12.2015, 03:40 by Zahra Homayoon, Joel M. Bowman, Francesco A. Evangelista
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.