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Updated: Aug 23, 2026

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
Rotation-tunneling analysis of the origin band in the tropolone pi(*)<--pi absorption system
Alfredo E Bracamonte1, Patrick H Vaccaro
1Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, USA.
Abstract:
The tunneling-split origin band of the tropolone A (1)B(2)-X (1)A(1) (pi(*)<--pi) absorption system was interrogated under ambient, bulk-gas conditions by exploiting high-resolution degenerate four-wave mixing techniques. The inherent complexity of this spectral region was alleviated by performing polarization-resolved measurements, with judicious selection of transverse characteristics for the incident and detected electromagnetic fields enabling rovibronic transitions to be discriminated according to their attendant changes in rotational angular momentum, DeltaJ. Quantitative simulation of recorded data sets showed the vibrationless level of the electronically excited state to be bifurcated by Delta(0) (A)=19.846(25) cm(-1), representing a factor of 20 increase in proton-transfer efficiency over the corresponding level of the ground electronic state. Spectroscopic parameters extracted for the 0(+) and 0(-) manifolds of A (1)B(2) tropolone yield unexpectedly large values of the inertial defect, DeltaI(0(+) ) (A)=-0.802(86) amu A(2) and DeltaI(0(-) ) (A)=-0.882(89) amu A(2), strongly suggesting that a loss of molecular planarity accompanies the pi(*)<--pi electron promotion. These results, as well as complementary information deduced for interloping hot-band resonances, are discussed in terms of the unique structural and dynamical properties exhibited by tropolone and related proton-transfer species.
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