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

Abstract

The mode specificity of proton-transfer dynamics in the ground electronic state (X (1)A(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) approximately 550-750 cm(-1)) vibrational features, assigned to nu(30)(a(1)), nu(32)(b(2)), and nu(31)nu(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.

Production of a beam of highly vibrationally excited CO using perturbations

“…SEP spectroscopy has been proven applicable to a wide variety of molecules. These include: I 2 , 5 C 2 H 2 , 7 CH 2 O, 8 NO, 9,10 HCN, 11,12 H(or D)FCO, 13,14 HCP, 15,16 Tropolone, 17,18 CS 2 , 19, 20 SO 2 , 21 SCCl 2 , 22 CH 3 O, 23 HCO, 24 and O 2 . 25,26 See Refs.…”

Vibrational specificity of proton-transfer dynamics in ground-state tropolone

“…To elucidate the influence of vibrational motion on large-amplitude hydron dynamics, the present work has implemented a fully coherent variant of the venerable stimulated emission pumping (SEP) technique 45 within the framework of two-color resonant four-wave mixing (TC-RFWM) spectroscopy. 46,47 This approach builds upon the basic paradigm of SEP, whereby two narrow-band sources of tunable laser light, commonly referred to as the PUMP and the DUMP, drive an inverted optical-optical double-resonance process designed to probe excited regions of the ground electronic manifold. For our TC-RFWM adaptation, a single PUMP field (i.e., having angular frequency o 1 and angular wavevector k 1 ) is fixed on a preselected rovibronic feature in the TrOH A ˜1B 48 This TC-RFWM scheme exhibits several unique characteristics, including laser-limited spectral resolution and true double-resonance response combined with high spatial, temporal, and polarization selectivity, which make it ideally suited for spectroscopic investigations of tropolone dynamics.…”

“…For our TC-RFWM adaptation, a single PUMP field (i.e., having angular frequency o 1 and angular wavevector k 1 ) is fixed on a preselected rovibronic feature in the TrOH A ˜1B 48 This TC-RFWM scheme exhibits several unique characteristics, including laser-limited spectral resolution and true double-resonance response combined with high spatial, temporal, and polarization selectivity, which make it ideally suited for spectroscopic investigations of tropolone dynamics. 46 In particular, the lowest-lying 1700 cm À1 portion of the X ˜1A 1 potential surface has been interrogated, uncovering numerous state-specific tunneling doublets and enabling definitive assignment of attendant fundamental, overtone, and combination bands.…”

Double proton transfer in the and states of the tropolone • HF complex

“…It is hoped that our efforts will serve to stimulate forthcoming spectroscopic investigations of the prototypical TrOH Á HF complex, as well as complementary dynamical simulations (akin to those already undertaken for TrOH) [52] designed to explore the electronic-/ vibrational-specificity of multidimensional double proton-transfer processes. The highly resolved experimental measurements already available for the analogous electronic manifolds of the bare tropolone molecule [43,53,54] should provide a springboard for these studies.…”