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Single-Molecule Spectral Fluctuation Originates from the Variation in Dipole Orientation Connected to Accessible
Aranyak Sarkar1,2, Vinu Namboodiri1, Manoj Kumbhakar1,2
1Radiation & Photochemistry Division, Bhabha Atomic Research Center, Mumbai, Maharashtra 400085, India.
Single molecule spectral fluctuations are linked to emission dipole reorientation. This study reveals how vibrational modes drive these changes, enabling new optical nanoscopy techniques.
Area of Science:
- Single-molecule spectroscopy
- Physical chemistry
- Spectroscopy
Background:
- Fluorescence fluctuations in single molecules are attributed to structural changes and environmental influences.
- The link between spectral fluctuations and emission dipole orientation changes remains unclear.
Purpose of the Study:
- To investigate the relationship between spectral fluctuations and dipole orientation in single molecules.
- To elucidate the mechanisms underlying these molecular behaviors.
Main Methods:
- Utilized single-molecule multidimensional tracking.
- Simultaneously monitored emission spectra and 3D dipole orientation of individual fluorophores at room temperature.
Main Results:
- Established a correlation between spectral fluctuations and dipole rearrangements.
- Identified variations in radiative relaxation probabilities and vibrational mode interactions as drivers of spectral fluctuations.
- Observed significant out-of-plane dipole reorientations during spectral jumps, linked to vibrational mode transitions.
Conclusions:
- Spectral fluctuations are driven by vibrational mode dynamics and dipole reorientation.
- This understanding opens possibilities for vibrational spectroscopy and specific optical nanoscopy.
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