Mode-specific tunneling dynamics in the ground electronic state of tropolone

摘要

The mode specificity of proton-transfer dynamics in the ground electronic state(X ~1A_1)of tropolone has been explored at near-rotational resolution by implementing a fully coherent variant of stimulated emission pumping within the framework of two-color resonant four-wave mixing spectroscopy.Three low-lying(E_(vib)≈ 550-750 cm~(-1))vibrational features,assigned to v_(30)(a_1),v_(32)(b_2),and v_(31)v_(38)(a_1),have been interrogated under ambient,bulk-gas conditions,with term energies determined for the symmetric and antisymmetric(tunneling)components of each enabling the attendant tunneling-induced bifurcations of 1.070(9),0.61(3),and 0.07(2)cm~(-1)to be extracted.The dependence of tunneling rate(or hydron migration efficiency)on vibrational motion is discussed in terms of corresponding atomic displacements and permutation-inversion symmetries for the tropolone skeleton.