Watching Ultrafast Molecular Motions with 2D IR Chemical Exchange Spectroscopy

Watching Ultrafast Molecular Motions with 2D IR Chemical Exchange Spectroscopy
Author: Michael D. Fayer
Publisher: World Scientific
Total Pages: 383
Release: 2011
Genre: Science
ISBN: 9814355623

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This unique volume presents a comprehensive but accessible introduction to the field of ultrafast two-dimension infrared (2D IR) vibrational echo spectroscopy based on the pioneering work of Professor Michael D Fayer, Department of Chemistry, Stanford University, USA. It contains in one place a qualitative introduction to the field of 2D IR spectroscopy and a comprehensive set of scientific papers that underlie the qualitative discussion. The introductory material contains several detailed illustrations, and is based on the Centenary Lecture at the Indian Institute of Science given by Professor Fayer July 16, 2008 as part of the celebration of the 100th anniversary of the founding of IIS in Bangalore, India. The second part of the volume contains reprints of Fayer's relevant papers. The compilation will be very useful because it presents the historical background, motivation, methodology, and experimental results at a level that is accessible to the non-expert. The reprints of the scientific papers, from review articles to detailed theoretical papers, provide rigorous supporting material so that the reader can delve as deeply as desired into the subject.

Ultrafast Infrared Vibrational Spectroscopy

Ultrafast Infrared Vibrational Spectroscopy
Author: Michael D. Fayer
Publisher: CRC Press
Total Pages: 491
Release: 2013-03-04
Genre: Science
ISBN: 1466510137

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The advent of laser-based sources of ultrafast infrared pulses has extended the study of very fast molecular dynamics to the observation of processes manifested through their effects on the vibrations of molecules. In addition, non-linear infrared spectroscopic techniques make it possible to examine intra- and intermolecular interactions and how such interactions evolve on very fast time scales, but also in some instances on very slow time scales. Ultrafast Infrared Vibrational Spectroscopy is an advanced overview of the field of ultrafast infrared vibrational spectroscopy based on the scientific research of the leading figures in the field. The book discusses experimental and theoretical topics reflecting the latest accomplishments and understanding of ultrafast infrared vibrational spectroscopy. Each chapter provides background, details of methods, and explication of a topic of current research interest. Experimental and theoretical studies cover topics as diverse as the dynamics of water and the dynamics and structure of biological molecules. Methods covered include vibrational echo chemical exchange spectroscopy, IR-Raman spectroscopy, time resolved sum frequency generation, and 2D IR spectroscopy. Edited by a recognized leader in the field and with contributions from top researchers, including experimentalists and theoreticians, this book presents the latest research methods and results. It will serve as an excellent resource for those new to the field, experts in the field, and individuals who want to gain an understanding of particular methods and research topics.

Dynamic IR Peak Coalescence and Ultrafast Chemical Exchange Reactions Studied by Two Dimensional Infrared Spectroscopy

Dynamic IR Peak Coalescence and Ultrafast Chemical Exchange Reactions Studied by Two Dimensional Infrared Spectroscopy
Author: Matthew Cody Zoerb
Publisher:
Total Pages: 150
Release: 2012
Genre:
ISBN:

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Vibrational spectroscopy is one of the most powerful techniques in chemistry due to its ability to report direct information on the geometries and nuclear motions of complex molecules. At thermal equilibrium, rearrangements between different, or equivalent, molecular structures help to define the reactivity of the system. On the ultrafast timescale, these chemical exchange reactions may cause features in the vibrational spectrum to become averaged. The Bloch equations have been used previously to quantitatively predict the rates of such reactions. This approach has been quite successful in NMR spectroscopy where exchange on the microsecond timescale is often sufficient to cause peak coalescence. The application of the Bloch equations to IR spectroscopy has been debated due to the presence of other contributions to the vibrational lineshape that may prevent an accurate description of the relevant dynamics. Two dimensional infrared spectroscopy (2D-IR) is a time resolved ultrafast technique that is capable of directly measuring the kinetics of chemical exchange at thermal equilibrium where there is no net change in the populations of reactants and products. This work examines two model systems that display dynamic IR peak coalescence. A group of mixed valence dimers of trinuclear ruthenium clusters have exhibited a wide range of IR coalescence that is sensitive to solvent, temperature, and ligand substitution. No electron exchange was observed by 2D-IR during the timescale required for peak coalescence. The two isomers of a square pyramidal ruthenium dithiolene compound also result in highly coalesced spectra. The equilibrium populations, as well as the extent of peak coalescence, are strongly dependent on temperature and solvent. The experimental results of this second project were largely inconconclusive; however, future work with density functional theory calculations looks promising for revealing more information on these dynamics. Ultimately, the application of the Bloch equations to IR spectra is not generally reliable. While this type of analysis may still yield accurate results in some special cases, it is very difficult to distinguish legitimate exchange induced coalescence from similar broadened lineshape features, and this approach should be avoided.

Analysis and Control of Ultrafast Photoinduced Reactions

Analysis and Control of Ultrafast Photoinduced Reactions
Author: Oliver Kühn
Publisher: Springer Science & Business Media
Total Pages: 854
Release: 2007-07-05
Genre: Science
ISBN: 3540680381

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This book summarizes several years of research carried out by a collaboration of many groups on ultrafast photochemical reactions. It emphasizes the analysis and characterization of the nuclear dynamics within molecular systems in various environments induced by optical excitations and the study of the resulting molecular dynamics by further interaction with an optical field.

Ultrafast Phenomena XV

Ultrafast Phenomena XV
Author: Paul Corkum
Publisher: Springer Science & Business Media
Total Pages: 853
Release: 2007-07-10
Genre: Science
ISBN: 3540687793

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This volume is a collection of papers presented at the Fifteenth International Conference on Ultrafast Phenomena held at the Asilomar Conference Grounds, Pacifc Grove, CA, USA, from July 31 – August 4, 2006. The Ultrafast P- nomena conferences are held every two years and provide a forum for disc- sion of the latest results in ultrafast optics and their applications in science and engineering. These meetings bring together researchers spanning several felds of science and engineering to discuss and debate the latest advances in ult- fast science. This unique forum provides a conduit for the greater dissemi- tion of the latest advances using ultrashort coherent pulses of light. More than 280 papers were presented. Signifcant progress in creating ever shorter pulses of light was reported in the attosecond range, with new applications in high harmonic generation and frequency comb metrology. Multidimensional sp- troscopy is rapidly evolving to provide new insights into quantum coherence and interactions in complex systems. Improvements in time resolved electron and x-ray diffraction provide better atomic scale perspectives on structural dynamics. These examples are but a small subset of the collected works ga- ered in this volume, which provides a valuable synopsis of the recent advances and impact of ultrafast technology in illuminating fundamental processes in physics, chemistry, and biology. There were 323 attendees at the meeting, more than one third of which were graduate and postdoctoral students. Increased s- dent attendance energized the proceedings.

Multidimensional Time-Resolved Spectroscopy

Multidimensional Time-Resolved Spectroscopy
Author: Tiago Buckup
Publisher: Springer
Total Pages: 320
Release: 2018-12-07
Genre: Science
ISBN: 3030024784

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The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.

Ultrafast Time-resolved Infrared Spectroscopy of Molecular Monolayers and Solute-solvent Complexes

Ultrafast Time-resolved Infrared Spectroscopy of Molecular Monolayers and Solute-solvent Complexes
Author: Daniel Edward Rosenfeld
Publisher:
Total Pages:
Release: 2012
Genre:
ISBN:

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Ultrafast time-resolved infrared spectroscopy has been a powerful tool in resolving and studying ultrafast motions in bulk chemical and biological systems. The utility of ultrafast time-resolved infrared spectroscopy is illustrated through two studies of solute-solvent complexes. The same experimental methods used to study bulk systems are then extended to study surface systems through the development of both surface molecular probes and new spectroscopic techniques. Ultrafast polarization and wavelength selective IR pump-probe spectroscopy is used to measure the inertial and long time orientational dynamics of pi-hydrogen bonding complexes. The complexes studied are composed of phen-d-ol (phenol-OD) and various pi-base solvents with different electron donating or withdrawing substituents. The inertial motion is found to be insensitive to the strength of the hydrogen bond, but highly sensitive to the local solvent structure as reported on by inhomogeneous line broadening. The local solvent structure therefore acts as the controlling influence in determining the extent of inertial orientational relaxation, and thus the angular potential. Variation in the pi-hydrogen bond strength is of secondary importance. Hydrogen bonded complexes between phenol and phenylacetylene are studied using ultrafast two-dimensional infrared (2D IR) chemical exchange spectroscopy. Phenylacetylene has two possible pi-hydrogen bonding acceptor sites (phenyl or acetylene) that compete for hydrogen bond donors in solution at room temperature. The chemical exchange process occurs in ~5 ps, and is assigned to direct hydrogen bond migration along the phenylacetylene molecule. The observation of direct hydrogen bond migration can have implications for macromolecular systems. 2D IR vibrational echo spectroscopy and heterodyne detected transient grating (HDTG) spectroscopy (an ultra-sensitive analog of pump-probe spectroscopy) are developed as means of study of the structural and vibrational dynamics of surfaces. The surfaces studied are silica surfaces functionalized with a transition metal carbonyl complex, tricarbonyl (1,10)-phenanthroline rhenium chloride. The functionalization process produces chromophore surface density of 1-2 × 10^14 per cm squared. The high surface density achieved indicates that energy transfer between molecules on the surface could impact the experimental observables probed in 2D IR and HDTG spectroscopy. The theory of excitation transfer induced spectral diffusion has been developed and is capable of calculating the effect of the energy transfer on any spectroscopic observable through a master equation approach. Initial estimates of surface structural dynamics, based on both experimental 2D IR data and theoretical calculations, showed sub-100ps structural dynamics in the molecular monolayers even without the presence of solvent. Furthermore, solvent is shown to accelerate the structural dynamics in a manner that is different from that of bulk solution. Additional surface density dependent experiments indicate the negligible nature of excitation transfer even in these dense systems. The functionalized molecular monolayers are found to have a ~40 ps structural dynamics relaxation time in the absence of solvent. Further investigation of the effects of solvents on the RePhen(CO)3Cl monolayers has been carried out. Immersion in solvent is found to change the infrared spectrum, structural dynamics and vibrational dynamics in ways that differ from the changes evidenced in the bulk. The monolayers were immersed in both solvents that can dissolve RePhen(CO)3Cl and those that cannot. For both hexadecane and D2O, which cannot dissolve the headgroup, the structural dynamics of the monolayer are slowed by the presence of solvent while the vibrational dynamics are not impacted. Polar organic solvents, which can dissolve the headgroup, accelerate the dynamics. Dimethylformamide (DMF) is found to have a particularly strong effect on the structural dynamics of the monolayers, accelerating the timescale from 40 ps to 15 ps, yet DMF has little impact on the vibrational dynamics. Chloroform is found to enhance the vibrational lifetime of the CO symmetric stretch of the RePhen(CO)3Cl headgroups in the monolayer by 50%. These results indicate that the properties of thin films can be modified by the presence of solvent, even in the case when the solvent is repelled by the monolayer.

Chemical Applications of Ultrafast Spectroscopy

Chemical Applications of Ultrafast Spectroscopy
Author: Graham R. Fleming
Publisher: Oxford University Press, USA
Total Pages: 280
Release: 1986
Genre: History
ISBN:

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The recent improvements in the techniques for producing very short duration pulses of laser light have allowed chemists to study processes taking place on similarly short timescales, now typically in the range of 10 to 10 seconds. This book describes methods for generating and characterising picosecond pulses, and then provides a discussion of current experimental techniques for the study of ultrafast chemical processes. The applications to specific chemical problems are divided into chapters on the vapour, liquid, and solid phases.