Monitoring Vibrational Evolution in Jahn-Teller Effect by Raman Imaging

TL;DR

This paper demonstrates that Raman imaging can visualize vibrational changes caused by the Jahn-Teller effect in single molecules, providing a new way to observe symmetry breaking in molecular systems.

Contribution

It introduces a practical Raman imaging protocol to monitor vibrational evolutions and symmetry breaking due to the Jahn-Teller effect at the single-molecule level.

Findings

Raman images reveal degenerate vibrational splitting in JTE

Vibration mixing caused by JTE can be characterized

JTE distortion can be controlled via isotopic substitution

Abstract

The Jahn-Teller effect (JTE) reduces the geometrical symmetry of a system with degenerate electronic states via vibronic coupling, playing a pivotal role in molecular and condensed systems. In this Letter, we propose that vibrational resolved tip-enhanced Raman scattering images can visualize the vibrational evolutions in JTE in real space. Taking an experimentally viable single zinc phthalocyanine (ZnPc) molecule as a proof-of-principle example, not only the degenerate vibrational splitting but also the overlooked vibration mixing caused by the JTE in its anionic form can be straightforwardly characterized by Raman images. Leveraging Raman images, the controllable configuration of JTE distortion with partial isotopic substitution could be further identified. These findings establish a practical protocol to monitor the detailed vibrational evolutions when a single molecule experiences JTE, opening a door for visualization of spontaneous symmetry breaking in molecular and solid-state systems.