Coherent multidimensional vibrational spectroscopy

Abstract

Coherent multidimensional vibrational spectroscopy (CMDVS) is an emerging ®eld that o ers new oportunities to probe speci®cally intramolecular and intermolecular interactions in complex samples with the improved resolution and selectivity expected of a multidimensional method. In particular, it provides structural and dynamical information about correlations between modes. It provides this information on the picosecond time scales characteristic of vibrational dephasing. CMDVS is based on the perturbations that are induced in a mode when other coupled modes are excited. It is the vibrational analogue to multidimensional nucler magnetic resonance (NMR). In this review, we present the background that led to the development of CMDVS, a brief summary of the di erent methods of non-linear laser spectroscopy and how they can achieve CMDVS, the relationships between CMDVS and multidimensional NMR, and the theory necessary to understand the experimental results. The experimental approaches reviewed fall into three main classes: non-degenerate four-wave mixing which is doubly vibrationally enhanced, degenerate four-wave mixing which is triply vibrationally enhanced and six-wave mixing which has three Raman transitions. CMDVS has been implemented in both the time domain and the frequency domain. Finally, the review describes possible extensions of CMDVS and speculates on its future.

Folding dynamics of a small protein at room temperature via simulated coherent two-dimensional infrared spectroscopy

“…The possible vibrational coupling between protein backbone amide units and side chains such as Asp or Glu is neglected. The fundamental frequency shift of the isotope-substituted amide I vibration is À67 cm À1 for 13 CQ 18 O and À43 cm À1 for 13 CQ 16 O in our simulation. The quasiparticle representation of optical response is used in the 2DIR calculation by solving the nonlinear exciton equations (NEE), which avoids the explicit calculation of the two-exciton states.…”

“…As pointed out above, the hydrogen bond pairs Ala7-Ala11, Lys8-Glu12, and Arg9-Ala13 are formed much slower and their formation indicates the completion of the helix folding. Using isotope-labeling on residue Lys8 ( 13 CQ 18 O substitution for 12 CQ 16 O) and Ala11( 13 CQ 16 O substitution for 12 CQ 16 O), we are able to single out the two residues and take a closer look at their structural change during folding. The 13 CQ 18 O substituted amide I vibration is usually red-shifted by approximately 60-70 cm À1 , thus separated from the Fig.…”

“…Over the last two decades, coherent two-dimensional infrared spectroscopy (2DIR) [10][11][12][13][14][15][16][17][18][19][20][21][22] has emerged as a powerful experimental technique that enables us to probe protein structure and dynamics at unprecedented time resolution-pico or even femto second. This was made possible by using ultrafast laser pulses.…”

Time‐Resolved Optical Spectroscopy with Multiple Population Dimensions: A General Method for Resolving Dynamic Heterogeneity

“…The expansion, elaboration and application of coherence methods [2] continues to this day in NMR, [3] electronic, [4,5] infrared [6][7][8] and Raman [9][10][11] spectroscopy. The key feature in the original spin echo-and in all subsequent coherence spectroscopies as well-is a comparison of the evolution of a coherence over two different time periods.…”

Quantum mechanical investigation of femtosecond stimulated Raman spectroscopy

“…pulses have also been proposed for their ability to sensitively and selectively reveal the vibrational anharmonic coupling strengths, to study the relative strength of homogeneous and inhomogeneous line broadening, and to determine the Duschinsky terms in the Taylor series of the molecular polarizability [68,129,130,131,132,133,134,135,136,137].…”