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Pump-Probe Noise Spectroscopy of Molecular Junctions
Maicol A Ochoa, Yoram Selzer1, Uri Peskin2
1‡School of Chemistry, Tel-Aviv University, Tel Aviv 69978, Israel.
The Journal of Physical Chemistry Letters
|August 12, 2015
Summary
Pump-probe spectroscopy struggles with slow electronic components. A new dc shot noise spectroscopy method offers sub-picosecond resolution for intramolecular dynamics, overcoming limitations of standard dc current measurements.
Area of Science:
- Physical Chemistry
- Materials Science
- Spectroscopy
Background:
- Pump-probe spectroscopy is limited by slow electronic component responses in junctions, hindering sub-picosecond intramolecular dynamics assessment.
- Recent proposals suggested dc current measurements could achieve picosecond resolution, but this approach has limitations.
Purpose of the Study:
- To re-evaluate the feasibility of picosecond resolution using pump-probe spectroscopy via dc measurements.
- To identify limitations of dc current measurements for intramolecular dynamics.
- To propose an alternative spectroscopy technique for enhanced temporal resolution.
Main Methods:
- Revisiting pump-probe spectroscopy principles applied to dc measurements.
- Analyzing the limitations of dc current measurements for charge transfer dynamics.
- Developing and presenting numerical examples for pump-probe dc shot noise spectroscopy.
Main Results:
- Standard dc current measurements miss intramolecular dynamics not directly related to charge transfer along the measurement direction.
- Pump-probe dc shot noise spectroscopy is proposed as a viable alternative for sub-picosecond resolution.
- Numerical simulations demonstrate the time-dependent and average responses of junctions using generic models.
Conclusions:
- Direct dc current measurements are insufficient for comprehensive intramolecular dynamics studies at the picosecond scale.
- Pump-probe dc shot noise spectroscopy provides a promising avenue for high-time-resolution investigations of molecular processes in junctions.
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