Related Experiment Video
Updated: Jun 27, 2025
09:57
Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems
Published on: February 10, 2020
7.2K
Resonant Tip-Enhanced Raman Spectroscopy of a Single-Molecule Kondo System.
Rodrigo Cezar de Campos Ferreira1, Amandeep Sagwal1,2, Jiří Doležal1,3
1Institute of Physics, Czech Academy of Sciences; Cukrovarnická 10/112, Praha 6 CZ16200, Czech Republic.
ACS Nano
|May 7, 2024
Summary
Tip-enhanced Raman spectroscopy (TERS) can now probe molecular spin states. This study reveals TERS can capture spin information in single molecules, opening doors for novel spin-optical devices.
Area of Science:
- Nanoscience
- Spectroscopy
- Quantum Chemistry
Background:
- Tip-enhanced Raman spectroscopy (TERS) under ultrahigh vacuum and cryogenic conditions allows for detailed studies of molecular properties.
- Exploring the relationship between molecular adsorption geometry, electronic state, and vibrational fingerprints is crucial for nanoscale science.
- The ability of TERS to reflect spin states in open-shell molecular configurations remains an underexplored area.
Purpose of the Study:
- To investigate the unexplored capability of TERS in reflecting spin states of individual molecules.
- To establish a correlation between Kondo resonance and TERS measurements in a specific molecular system.
- To demonstrate the potential of TERS for designing single-molecule spin-optical devices.
Main Methods:
- Utilized scanning probe microscopy with a metallic tip to manipulate individual perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecules.
- Performed ultrahigh vacuum and cryogenic tip-enhanced Raman spectroscopy (TERS) and differential conductance spectroscopy.
- Employed theoretical simulations to assign vibrational spectra and identify molecular modes.
Main Results:
- Successfully lifted PTCDA molecules into an open-shell spin one-half anionic state using the SPM tip.
- Observed a correlation between the Kondo resonance in differential conductance spectroscopy and characteristic changes in TERS measurements.
- Identified that Raman scattering on suspended PTCDA is resonant with a higher excited state.
- Assigned TERS peaks to high-symmetry Ag modes, including fingerprints of the observed spin state, via theoretical simulations.
Conclusions:
- TERS can capture complex interactions between charge, spin, and photophysical properties in nanoscale molecular systems.
- The study demonstrates a pathway for designing single-molecule spin-optical devices by leveraging TERS.
- TERS provides a powerful tool for probing spin-dependent phenomena at the single-molecule level.
Related Concept Videos
01:20Raman Spectroscopy: Overview
365
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
365
01:12Double Resonance Techniques: Overview
199
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
199
01:26Raman Spectroscopy Instrumentation: Overview
331
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
331
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
831
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
831