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Observation of an isomerizing double-well quantum system in the condensed phase



Varun Verma, Jascha A. Lau, Arnab Choudhury, Li Chen, Dirk Schwarzer, Alec M. Wodtke


Molecules are quantum objects; therefore, isomerization fundamentally involves quantum states bound within a molecular potential energy function with multiple minima. For isolated gas-phase molecules, eigenstates well above the isomerization saddle points have been characterized. However, to observe the quantum nature of isomerization, we must study model systems where transitions between the eigenstates occur, for example in condensed phases. Unfortunately, resolving quantum states with spectroscopic tools fails for most condensed phase systems. An exception is adsorbed CO on NaCl(100), which is bound with the well-known OC-Na+ structure. In this work, we observe an unexpected upside-down isomer (CO-Na+ produced by infrared laser excitation and we obtain well-resolved infrared fluorescence spectra from highly energetic vibrational states of both orientational isomers. We assign the spectra using a simple electrostatic model. This remarkable condensed phase system is ideally suited to spectroscopic investigations of the quantum nature of isomerization and may have applications for atomic scale information storage.


quantum, condensed phase, superconducting nanowire, single-photon detector, mid-infrared


Verma, V. , Lau, J. , Choudhury, A. , Chen, L. , Schwarzer, D. and Wodtke, A. (2020), Observation of an isomerizing double-well quantum system in the condensed phase, Science (Accessed April 17, 2024)
Created January 10, 2020, Updated May 5, 2023