1. Slides for PowerPoint: Nonlinear and Two-Dimensional Spectroscopy
Andrei Tokmakoff
MIT Department of Chemistry

2. Complete Slides

3. Why 2D IR Spectroscopy? IR spectroscopy
IR probes vibrations intrinsic to all molecules
Each vibration gives different information
Structure and dynamics
Intrinsic time-scale of ~1 ps
2D IR spectroscopy: A more sensitive probe
Characterize vibrational correlations
Couplings, orientation, exchange
Resolves congested spectra & suppresses inhomogeneous broadening
Quantitative structure-based modeling

4. Fourier transform 2D IR spectroscopy

5. Ultrafast nonlinear spectroscopy
mask

6. Polarization-selective pump-probe experiment
Magic Angle: Vibrational Lifetime
Anisotropy: Reorientation

7. Peak Shift Measurement
ta – tb (fs)

8. 2D IR Interferometer
time/frequency
detection
time/time
detection

9. 2D IR Spectroscopy in pump-probe geometry

10. Obtaining an Absorptive 2D IR Spectrum

11. 2D IR spectroscopy t2 > tc t2 = 0 Related to the joint probability
Frequency Fluctuations
Vibrational Couplings
Chemical Exchange

12. Chemical exchange and spectral diffusion
Excite: Initial frequency w1
Wait for period t2
Detect: Final frequency w3
t2 → 
t2 = 0

13. 2D lineshapes: Loss of frequency correlation
Absorptive
Phase
Ellipticity a b
Phase slope

14. Extra Graphics

15. 2D Lineshapes

16. Rephasing and Non-rephasing

17. Rephasing and Non-rephasing

18. 2D IR Spectrum of RDC in Hexane

19. 2D IR Spectrum of RDC in Hexane

20. Polarization-Selective 2D IR Spectroscopy

21. Projection Angle from Peak Amplitudes