Design strategies for pulse sequences in multidimensional optical spectroscopies

Scheurer, Christoph; Mukamel, Shaul

doi:10.1063/1.1391266

Cited by 88 publications

(98 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, structural information is lost when the crosspeaks overlap with the more intense diagonal peaks. Methods have been developed in 2D NMR to minimize the overlap of diagonal and crosspeaks (9,10). Here we report a technique based on quite different principles that completely eliminates the diagonal peaks from 2D IR spectra and allows the crosspeaks and hence structures to be more easily and better characterized.…”

Section: H Eterodyned 2d Ir Experiments Have Recently Been Reportedmentioning

confidence: 99%

Two-dimensional IR spectroscopy can be designed to eliminate the diagonal peaks and expose only the crosspeaks needed for structure determination

Zanni

Kim

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

290

291

View full text Add to dashboard Cite

The power of two-dimensional (2D) IR spectroscopy as a structural method with unprecedented time resolution is greatly improved by the introduction of IR polarization conditions that completely eliminate diagonal peaks from the spectra and leave only the crosspeaks needed for structure determination. This approach represents a key step forward in the applications of 2D IR to proteins, peptides, and other complex molecules where crosspeaks are often obscured by diagonal peaks. The technique is verified on the model compound 1,3-cyclohexanedione and subsequently used to clarify the distribution of structures that the acetylproline-NH 2 dipeptide adopts in chloroform. In both cases, crosspeaks are revealed that were not observed before, which, in the case of the dipeptide, has led to additional information about the structure of the amino group end of the peptide.H eterodyned 2D IR experiments have recently been reported that are the IR analogues of pulsed correlated spectroscopy and nuclear Overhauser effect spectroscopy in 2D NMR (1-5). Like 2D NMR spectra that exhibit diagonal peaks at frequencies determined by one-dimensional spectra and crosspeaks between coupled nuclear spins, 2D IR spectra contain diagonal peaks and crosspeaks that represent coupled vibrational transitions. The 2D IR crosspeak intensities and splittings depend on the angles and distances between the vibrational modes and can be used to characterize the structures of peptides (3, 6, 7). One advantage (8) of 2D IR over other structure-determining methods is the time scale; 2D IR can monitor structures on a picosecond timescale, which allows transient protein dynamics to be followed. However, structural information is lost when the crosspeaks overlap with the more intense diagonal peaks. Methods have been developed in 2D NMR to minimize the overlap of diagonal and crosspeaks (9, 10). Here we report a technique based on quite different principles that completely eliminates the diagonal peaks from 2D IR spectra and allows the crosspeaks and hence structures to be more easily and better characterized.A useful characteristic of IR transitions is that the directions of their transition dipoles in the molecular frame are often predictable. For example, modes that are mainly localized on two atoms such as NOH, COH, or CAO stretches usually have transition dipole vectors near the bond axis, and the amide I modes of peptide units have transition dipoles whose directions are given by the positions of the amide atoms (11). The four polarized IR pulses in the 2D IR experiments successively interact with four transition dipoles of each molecule, and thus polarized 2D IR measurements can yield information on the geometric arrangements of the dipoles. The diagonal peaks are generated when the IR pulses all interact with the same mode and therefore interrogate only a single location in the structure. The crosspeaks are generated when the IR pulses interact with modes in different locations. The results are couplings and relative orientations that can be used t...

show abstract

Section: H Eterodyned 2d Ir Experiments Have Recently Been Reportedmentioning

confidence: 99%

Two-dimensional IR spectroscopy can be designed to eliminate the diagonal peaks and expose only the crosspeaks needed for structure determination

Zanni

Kim

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

290

291

View full text Add to dashboard Cite

show abstract

“…Using additional delay stages -like in the entangled-photon virtual state spectroscopy discussed above -these signals can be spread to create multidimensional fre- quency correlation maps, which carry information about couplings between different resonances or relaxation mechanisms (Ginsberg et al, 2009). Phase-cycling is essential for partially non-collinear or collinear geometry 2D spectroscopic experiments (Keusters et al, 1999;Krčmář et al, 2013;Scheurer and Mukamel, 2001;Tan, 2008;Tian et al, 2003;Yan and Tan, 2009;Zhang et al, 2012a). In phase-cycling protocol, the desired 2D signals are retrieved by the weighted summation of data collected using different interpulse phases, φ 21 , which are cycled over 2π radians in a number of equally spaced steps.…”

Section: Multidimensional Signalsmentioning

confidence: 99%

“…2b), each interaction with a field also imprints its phase φ onto the signal. Filtering the possible phase combinations ±φ 1 ± φ 2 ± φ 3 ± φ 4 of the signal, known as phase cycling, allows for the selective investigation of specific material properties Keusters et al, 1999;Krčmář et al, 2013;Scheurer and Mukamel, 2001;Tan, 2008;Tian et al, 2003;Zhang et al, 2012a,b). Acousto-optical modulation discussed in Fig.…”

Section: B Diagram Constructionmentioning

confidence: 99%

Nonlinear optical signals and spectroscopy with quantum light

2016

View full text Add to dashboard Cite

Conventional nonlinear spectroscopy uses classical light to detect matter properties through the variation of its response with frequencies or time delays. Quantum light opens up new avenues for spectroscopy by utilizing parameters of the quantum state of light as novel control knobs and through the variation of photon statistics by coupling to matter. We present an intuitive diagrammatic approach for calculating ultrafast spectroscopy signals induced by quantum light, focusing on applications involving entangled photons with nonclassical bandwidth properties -known as "time-energy entanglement". Nonlinear optical signals induced by quantized light fields are expressed using time ordered multipoint correlation functions of superoperators in the joint field plus matter phase space. These are distinct from Glauber's photon counting formalism which use normally ordered products of ordinary operators in the field space. One notable advantage for spectroscopy applications is that entangled photon pairs are not subjected to the classical Fourier limitations on the joint temporal and spectral resolution. After a brief survey of properties of entangled photon pairs relevant to their spectroscopic applications, different optical signals, and photon counting setups are discussed and illustrated for simple multi-level model systems.

show abstract

“…The improved resolution of k III stems from the absence of the diagonal peaks that dominate the k I signal and obscure the off-diagonal (cross) peaks, and from doubling the frequency bandwidth of two-quantum coherences. We have anticipated these advantages of k III based on the analogy with corresponding NMR pulse sequences (26)(27)(28). The additive third-order spectra are also displayed in Fig.…”

Section: Test Of Secondary Structure Additivity Of Coherent Spectramentioning

confidence: 99%

Dissecting coherent vibrational spectra of small proteins into secondary structural elements by sensitivity analysis

Zhuang

Abramavičius

Mukamel

2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The response of proteins to sequences of femtosecond infrared pulses provides a multidimensional view into their equilibrium distribution of structures and snapshot pictures of fast-triggered dynamical events. Analyzing these experiments requires advanced computational tools for assigning regions in the resulting multidimensional correlation plots to specific secondary-structure elements and their couplings. A differential sensitivity analysis technique based on a perturbation of the local (real space) Hamiltonian is developed to achieve that goal. Application to the amide I region of a small globular protein reveals regions associated with the ␣-helix, ␤-sheet, and their coupling. Comparison of signals generated in different directions shows that the double-quantumcoherence signal has a higher sensitivity to the couplings compared with the single-quantum-coherence (photon echo) technique.protein structure determination ͉ two-dimensional infrared P robing protein structure and folding pathways is one of the central problems of modern structural biology. Elaborate NMR pulse sequences are routinely used in the study of millisecond dynamical events in complex biomolecules with high spatial resolution (1). Optical response functions are particularly sensitive to structural features such as bond strengths, backbone angles, dipole moments, and polarizabilities, as well as the environmental factors that influence the structure such as hydrogen bond strengths and electric fields. Femtosecond optical techniques, thus, offer a good complimentary tool for monitoring fast protein motions and unraveling the underlying couplings between functional groups (2) in real time.Two-dimensional techniques introduced into NMR in the 1970s revolutionized its resolution and utility (1). Similarly, significant progress has been made over the past decade in developing 2D infrared (2DIR) spectroscopy, based on the application of sequences of femtosecond pulses, into a powerful tool for probing protein structure and providing snapshots of fast-triggered protein folding events (3-6).Spreading the information in two dimensions greatly enhances the resolution. Furthermore, 2DIR carries additional information regarding the fluctuations of two-exciton-state frequencies that is not available from linear (1D) spectra and provides a direct look at correlations among various segments of the protein. Cross peaks of 2DIR signals of equilibrated structures provide new structural constraints analogous to the nuclear Overhauser effect in 2D NMR. Structural information is extracted from multidimensional NMR data by using extensive simulations (7), through ''direct inversion'' based on constraint fits guided by simulations or structural optimizations. Their infrared analogues are less resolved, and anharmonic vibrational Hamiltonians are much more complex than spin Hamiltonians, making simulations an even more essential part of the analysis apparatus. Thanks to the ultrafast time scale, the simulation of 2DIR signals with atomic-level details only requires...

show abstract

Design strategies for pulse sequences in multidimensional optical spectroscopies

Cited by 88 publications

References 29 publications

Two-dimensional IR spectroscopy can be designed to eliminate the diagonal peaks and expose only the crosspeaks needed for structure determination

Two-dimensional IR spectroscopy can be designed to eliminate the diagonal peaks and expose only the crosspeaks needed for structure determination

Nonlinear optical signals and spectroscopy with quantum light

Dissecting coherent vibrational spectra of small proteins into secondary structural elements by sensitivity analysis

Contact Info

Product

Resources

About