Related Experiment Videos
Coherent vibrational climbing in carboxyhemoglobin.
Cathie Ventalon1, James M Fraser, Marten H Vos
1Centre National de la Recherche Scientifique Unité Mixte de Recherche 7645, Institut National de la Santé et de la Recherche Médicale, Ecole Polytechnique-Ecole Nationale Supérieure de Techniques Avancées, Palaiseau, France.
Summary
We observed vibrational climbing in carboxyhemoglobin using ultrashort pulses, reaching excited vibrational states up to v=6. This study provides key spectroscopic data for the CO stretch in strong fields.
Area of Science:
- Physical Chemistry
- Spectroscopy
- Chemical Physics
Background:
- Carboxyhemoglobin (COHb) is a crucial protein studied for its vibrational dynamics.
- Understanding vibrational energy transfer is key to protein function and drug interactions.
Purpose of the Study:
- To demonstrate and characterize vibrational climbing in the CO stretch of COHb.
- To investigate vibrational population inversion and obtain spectroscopic parameters in the strong-field regime.
Main Methods:
- Utilized mid-infrared chirped ultrashort pulses for excitation.
- Employed spectrally resolved pump-probe measurements to observe vibrational populations.
Main Results:
- Directly observed induced absorption lines for vibrational states up to v=6.
- Observed stimulated emission, indicating vibrational population inversion.
- Measured equally spaced vibrational transitions consistent with a Morse potential up to v=6.
- Noted deviations from the simple Morse model in differential absorption spectra.
Conclusions:
- Vibrational climbing in COHb's CO stretch is achievable with chirped ultrashort pulses.
- Spectroscopic parameters like transition frequencies and dephasing times were determined.
- The study reveals limitations of simple models in describing strong-field vibrational dynamics.