Expérimental
Two-dimensional infrared (2DIR) spectroscopy is a nonlinear optical method consisting in measuring a pump-probe spectrum which is frequency resolved in both pump and probe dimensions. It is sensitive to the coupling between vibrational modes of molecular systems and also to protein structure fluctuations. In collaboration with Laboratoire Charles Fabry (IOGS) and the Amplitude company, LOB has recently developed a new 2DIR spectrometer of unprecedented spectral resolution, thanks to a nonlinear optical method coined Chirped Pulse Upconversion allowing direct detection of MIR radiation with a visible CMOS camera. The proposed internship will consist in applying this new experiment to recording 2DIR spectra in carboxyhemoglobin and in carbon dioxide. In the latter case, the 2DIR spectrum will exhibit a large number of narrow lines associated to different rotational modes, thus evidencing the remarkable spectral resolution that can be achieved in both pump and probe dimensions. The experimental results will be compared with a numerical calculation based on a quantized rigid rotator model for calculating the 2D rovibrational spectrum.