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Coherent pump pulses in Double Electron Electron Resonance spectroscopy
1Department of Chemistry, University of Washington, Seattle, WA 98195, USA. stst@uw.edu.
Physical Chemistry Chemical Physics : PCCP
|June 25, 2016
Summary
Coherent pump pulses in Double Electron Electron Resonance (DEER) spectroscopy can create artefacts. New phase cycling schemes suppress these echoes, enabling accurate long-distance measurements with advanced DEER experiments.
Area of Science:
- Electron Paramagnetic Resonance (EPR) Spectroscopy
- Quantum Dynamics
- Spectroscopic Techniques
Background:
- Shaped pulses enhance sensitivity and control in Double Electron Electron Resonance (DEER) spectroscopy.
- Traditional DEER relies on incoherent pump channels to minimize coherent effects.
- Fully coherent EPR spectrometers necessitate explicit consideration of coherent pump pulse effects.
Purpose of the Study:
- To investigate the impact of coherent rectangular and sech/tanh pump pulses in DEER experiments.
- To analyze the generation and effects of spin echoes caused by coherence transfer pathways.
- To develop methods for suppressing artefacts in DEER experiments conducted on coherent EPR spectrometers.
Main Methods:
- Examination of DEER experiments utilizing up to three coherent pump pulses.
- Quantitative modeling of observed spin echoes using spin quantum dynamics and instrumental transfer functions.
- Development and demonstration of phase cycling schemes for artefact suppression.
Main Results:
- Coherent pump pulses, even with non-overlapping bandwidths, generate intense spin echoes via coherence transfer.
- These spin echoes act as artefacts, potentially leading to misinterpretation of DEER data.
- A quantitative model accurately describes the observed echo phenomena.
- Efficient phase cycling schemes effectively suppress echo artefacts.
Conclusions:
- Coherent pump pulses in DEER require careful management to avoid artefacts.
- The proposed phase cycling schemes enable the use of advanced DEER on coherent EPR spectrometers.
- This work facilitates high-sensitivity, accurate long-distance measurements in DEER spectroscopy.
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