Infrared ultrafast

Lian T, Kholodenko Y and Hochstrasser R M 1995 Infrared probe of the solvent response to ultrafast solvation processes J. Rhys. Chem. 99 2546-51... 

Beokerle J D, Casassa M P, Cavanagh R R, Heilweil E J and Stephenson J C 1990 Ultrafast infrared response of adsorbates on metal surfaoes vibrational lifetime of CO/Pt(111) Phys. Rev. Lett. 64 2090-3... 

Hill J R ef a/1996 Ultrafast infrared speotrosoopy in biomoleoules aotive site dynamios of heme proteins Biospectroscopy 2 277-99... 

Cwrutsky J C, Li M, Culver J P, Sarisky M J, Yodh A G and Hoohstrasser R M 1993 Vibrational dynamios of oondensed phase moleoules studied by ultrafast infrared speotrosoopy Time Resolved Vibrational Spectroscopy VI (Springer Proc. in Physics 74) ed A Lau (New York Springer) pp 63-7... 

Vibrational spectroscopy can help us escape from this predicament due to the exquisite sensitivity of vibrational frequencies, particularly of the OH stretch, to local molecular environments. Thus, very roughly, one can think of the infrared or Raman spectrum of liquid water as reflecting the distribution of vibrational frequencies sampled by the ensemble of molecules, which reflects the distribution of local molecular environments. This picture is oversimplified, in part as a result of the phenomenon of motional narrowing The vibrational frequencies fluctuate in time (as local molecular environments rearrange), which causes the line shape to be narrower than the distribution of frequencies [3]. Thus in principle, in addition to information about liquid structure, one can obtain information about molecular dynamics from vibrational line shapes. In practice, however, it is often hard to extract this information. Recent and important advances in ultrafast vibrational spectroscopy provide much more useful methods for probing dynamic frequency fluctuations, a process often referred to as spectral diffusion. Ultrafast vibrational spectroscopy of water has also been used to probe molecular rotation and vibrational energy relaxation. The latter process, while fundamental and important, will not be discussed in this chapter, but instead will be covered in a separate review [4],... 

P. Hamm and R. M. Hochstrasser, Structure and dynamics of proteins and peptides Femto second two dimensional infrared spectroscopy, in Ultrafast Infrared and Raman Spectroscopy, Markel Dekker, New York, 2001, p. 273. 

Bredenbeck J, Ghosh A, Smits M, Bonn M (2008) Ultrafast two dimensional-infrared spectroscopy of a molecular monolayer. J Am Chem Soc 130 2152... 

Here we report our exploration of the possibility of inducing an ultrafast non-Franck-Condon transition, which we defined to be the creation of a wave packet at the other turning point of the above-mentioned oscillation, see Fig. 1(b), faster than the time it takes the Franck-Condon packet to reach that turning point due to the natural (field-free) dynamics. We have explored two possible routes for inducing non-Franck-Condon transitions, namely phase-tailoring of a weak-field ultraviolet (UV) pulse [6] tmd a two-pulse scheme combining a transform limited weak-field UV pulse with a strong infrared (IR) field [7]. 

The complexity of the physical properties of liquid water is largely determined by the presence of a three-dimensional hydrogen bond (HB) network [1]. The HB s undergo continuous transformations that occur on ultrafast timescales. The molecular vibrations are especially sensitive to the presence of the HB network. For example, the spectrum of the OH-stretch vibrational mode is substantially broadened and shifted towards lower frequencies if the OH-group is involved in the HB. Therefore, the microscopic structure and the dynamics of water are expected to manifest themselves in the IR vibrational spectrum, and, therefore, can be studied by methods of ultrafast infrared spectroscopy. It has been shown in a number of ultrafast spectroscopic experiments and computer simulations that dephasing dynamics of the OH-stretch vibrations of water molecules in the liquid phase occurs on sub-picosecond timescales [2-14],... 

Recently, modem ultrafast spectroscopic methods have opened a new experimental window on the molecular dynamics of water, examining the OH-stretch dynamics for the experimentally convenient aqueous system of HOD diluted in D2O using ultrafast infrared (IR) [1-6], IR-Raman [7], or photon echo [8] spectroscopy. 

K.B. Mpller, R. Rey, J.T. Hynes, On Hydrogen Bond Dynamics in Water and Ultrafast Infrared Spectroscopy A Theoretical Study, to appear in J. Phys. Chem. A (2004). 

Bimodal intermolecular proton transfer in water photoacid-base pairs studied with ultrafast infrared spectroscopy... 

Transient two-dimensional infrared spectroscopy - towards measuring ultrafast structural dynamics... 

Although, relevant information about ferrous hemeproteins kinetics, dynamics and ligand photodissociation pathways has been obtain, less is known about ferric hemeproteins photophysic processes. Recent studies performed with Hbl-CN and Mb-CN at ultrafast time scale, have suggested that some of the transients intermediaries observed after ferrous complexes ligand photodissociation are observed in ferric Mb and Hbl [7], However, time-resolved infrared data shows that the complex remained six coordinated after photoexcitation. In this work we present ultrafast data on ferric Hbl-NO, HM-N3, HM-H2S and metHbl complexes that suggest a mechanism for the photoinduced reduction of Hbl species. 

Tunable operation with bandwidth-limited sub-10-fs pulses in the visible (550-700 nm) and near infrared (900-1300 nm) was also performed by changing the seed delay with respect to the pump after increasing the seed chirp [10]. The NOPA is one of most useful light sources for ultrafast spectroscopy in the present stage on an extremely short time scale. 

Ultrafast proton transfer. The diffusion-controlled limit for second-order rate constants (Section A3) is 1010 M 1 s 1. In 1956, Eigen, who had developed new methods for studying very fast reactions, discovered that protons and hydroxide ions react much more rapidly when present in a lattice of ice than when in solution.138 He observed second-order rate constants of 1013 to 1014 M 1 s These represent rates almost as great as those of molecular vibration. For example, the frequency of vibration of the OH bond in water is about 1014 s . The latter can be deduced directly from the frequency of infrared light absorbed in exciting this vibration Frequency v equals wave number (3710 cm-1 for -OH stretching) times c, the velocity of light (3 x 1010 cm s ). 

Long, Fayer, M.D. Ultrafast Infrared and Raman Spectroscopy. Marcel Dekker, Inc., New York, NY, 2001. 

D. Charge Resonance Band in the Near-Infrared Region and Ultrafast Dynamics for Styrylpyridinium Tetraphenylborate Salts... 

Brighter, tunable ultrafast light sources would benefit many of the areas discussed in the report, particularly infrared-terahertz (between visible light and radio waves) vibrational and dynamical imaging, near-field scanning optical microscopy (NSOM), and X-ray imaging. 

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