Attosecond Molecular Dynamics

Author: Marc J J Vrakking

Publisher: Royal Society of Chemistry

ISBN: 9781788015134

Category: Science

Page: 500

View: 769

Attosecond science is a new and rapidly developing research area in which molecular dynamics are studied at the timescale of a few attoseconds. Within the past decade, attosecond pump–probe spectroscopy has emerged as a powerful experimental technique that permits electron dynamics to be followed on their natural timescales. With the development of this technology, physical chemists have been able to observe and control molecular dynamics on attosecond timescales. From these observations it has been suggested that attosecond to few-femtosecond timescale charge migration may induce what has been called “post-Born-Oppenheimer dynamics”, where the nuclei respond to rapidly time-dependent force fields resulting from transient localization of the electrons. These real-time observations have spurred exciting new advances in the theoretical work to both explain and predict these novel dynamics. This book presents an overview of current theoretical work relevant to attosecond science written by theoreticians who are presently at the forefront of its development. It is a valuable reference work for anyone working in the field of attosecond science as well as those studying the subject.
Atomic and Molecular Dynamics Probed by Intense Extreme Ultraviolet Attosecond Pulses

Author: Jasper Georg Christopher Peschel


ISBN: 9180390153



View: 927

This thesis work was aimed to investigate dynamical processes in atoms and molecules on ultrafast time scales initiated by absorption of light in the extreme ultraviolet (XUV) regime. In particular, photoionization and photodissociation have been studied using pump-probe techniques involving ultrafast laser pulses. Such pulses are generated using either high-order harmonic generation (HHG) or free-electron lasers (FELs). The work of this thesis consists to a large extent in the development and application of a light source, enabling intense XUV attosecond pulses using HHG. In a long focusing geometry, a high-power infrared laser is frequency up-converted so as to generate a comb of high-order harmonics. An important aspect was the study of the spatial and temporal properties of the generated light pulses in order to gain control of their influence on the experiment. Combining theoretical and experimental results, the effect of the dipole phase on properties of high-order harmonics was explored, along with a metrological series of studies on the harmonic wavefront and the properties of the focusing optics used. Further, the HHG light source was employed to investigate photoionization. Individual angular momentum channels involved in the ionization were characterized using two-photon interferometry in combination with angle-resolved photoelectron detection. A method is applied allowing the full determination of channel-resolved amplitudes and phases of the matrix elements describing the single-photon ionization of neon. Finally, the process of photodissociation was investigated using light pulses generated via both HHG and FELs. The dissociation dynamics induced by multiple ionization of organic molecules were studied. Correlation techniques were used to unravel the underlying fragmentation dynamics, and additionally, pump-probe experiments provided insights into the time scales of the (pre-)dissociation dynamics.
Attosecond Spectroscopic Studies of Atomic and Molecular Dynamics

Author: Annelise Beck


ISBN: OCLC:919405379


Page: 104

View: 359

Isolated attosecond pulses with photon energies in the extreme ultraviolet have provided a new capability to study few-femtosecond and sub-femtosecond dynamics in atomic and molecular systems. A novel regime of attosecond transient absorption measurements, in which the near-infrared pulse follows the attosecond pulse, is reviewed. The observed timescales of the decay of an absorption feature and oscillations due to quantum beating are derived and experimental considerations for these measurements are discussed. Attosecond transient absorption spectroscopy is then applied to observe quantum beating between the 2s22p5(2P3/2)3d and 2s22p5(2P1/2)3d electronically excited states of neon. The quantum beating is observed more prominently in one of the absorption features, and theoretical models of the effect of the near-infrared pulse are proposed to explain this asymmetry and characterize the observed beating. In the model that most closely agrees with the measurement, the beating is detected via Rabi cycling induced by the near-infrared pulse through an intermediate state (likely one of the 3p states), and this mechanism is shown to be strongly dependent on the spectrum of the near-infrared pulse. The isolated attosecond pulses used in these experiments are characterized using the photoelectron streaking method and the duration of these pulses is measured by iteratively reconstructing the streaking spectrograms. The effect on the streaking spectrogram of various pulse characteristics, such as duration, chirp, and the presence of satellite pulses, is described. Streaking spectrograms using low photon energy attosecond pulses are typically asymmetric. The reasons for this asymmetry are discussed and the challenges of reconstructing these low energy pulses are addressed. Finally, attosecond pulses are used to investigate superexcited states, or doubly excited states above the ionization potential, of the nitrogen molecule (N2). These states can decay via two competing channels, autoionization and predissociation. Time-of-flight mass spectrometry is applied to measure lifetimes of these states. Preliminary results are presented and improvements to the experimental design are proposed.
Molecular Spectroscopy and Quantum Dynamics

Author: Roberto Marquardt

Publisher: Elsevier

ISBN: 9780128172353

Category: Science

Page: 374

View: 470

Molecular Spectroscopy and Quantum Dynamics, an exciting new work edited by Professors Martin Quack and Roberto Marquardt, contains comprehensive information on the current state-of-the-art experimental and theoretical methods and techniques used to unravel ultra-fast phenomena in atoms, molecules and condensed matter, along with future perspectives on the field. Contains new insights into the quantum dynamics and spectroscopy of electronic and nuclear motion Presents the most recent developments in the detection and interpretation of ultra-fast phenomena Includes a discussion of the importance of these phenomena for the understanding of chemical reaction dynamics and kinetics in relation to molecular spectra and structure
Multiphoton Processes and Attosecond Physics

Author: Kaoru Yamanouchi

Publisher: Springer Science & Business Media

ISBN: 9783642289484

Category: Science

Page: 416

View: 603

Recent advances in ultrashort pulsed laser technology have opened new frontiers in atomic, molecular and optical sciences. The 12th International Conference on Multiphoton Processes (ICOMP12) and the 3rd International Conference on Attosecond Physics (ATTO3), held jointly in Sapporo, Japan, during July 3-8, showcased studies at the forefront of research on multiphoton processes and attosecond physics. This book summarizes presentations and discussions from these two conferences.
Progress in Ultrafast Intense Laser Science XIV

Author: Kaoru Yamanouchi

Publisher: Springer

ISBN: 9783030037864

Category: Science

Page: 291

View: 969

This 14th volume in the PUILS series presents up-to-date reviews of advances in Ultrafast Intense Laser Science, an interdisciplinary research field spanning atomic and molecular physics, molecular science, and optical science, which has been stimulated by the rapid developments in ultrafast laser technologies. Each chapter begins with an overview of the topics to be discussed, so that researchers unfamiliar to the subfield, as well as graduate students, can grasp the importance and appeal of the respective subject matter; this is followed by reports on cutting-edge discoveries. This volume covers a broad range of topics from this interdisciplinary field, e.g. atoms and molecules interacting in intense laser fields, laser-induced filamentation, high-order harmonics generation, and high-intensity lasers and their applications.
Ultrafast Dynamics Driven by Intense Light Pulses

Author: Markus Kitzler

Publisher: Springer

ISBN: 9783319201733

Category: Science

Page: 379

View: 570

This book documents the recent vivid developments in the research field of ultrashort intense light pulses for probing and controlling ultrafast dynamics. The recent fascinating results in studying and controlling ultrafast dynamics in ever more complicated systems such as (bio-)molecules and structures of meso- to macroscopic sizes on ever shorter time-scales are presented. The book is written by some of the most eminent experimental and theoretical experts in the field. It covers the new groundbreaking research directions that were opened by the availability of new light sources such as fully controlled intense laser fields with durations down to a single oscillation cycle, short-wavelength laser-driven attosecond pulses and intense X-ray pulses from the upcoming free electron lasers. These light sources allowed the investigation of dynamics in atoms, molecules, clusters, on surfaces and very recently also in nanostructures and solids in new regimes of parameters which, in turn, led to the identification of completely new dynamics and methods for controlling it. Example topics covered by this book include the study of ultrafast processes in large molecules using attosecond pulses, control of ultrafast electron dynamics in solids with shaped femtosecond laser pulses, light-driven ultrafast plasmonic processes on surfaces and in nanostructures as well as research on atomic and molecular systems under intense X-ray radiation. This book is equally helpful for people who would like to step into this field (e.g. young researchers), for whom it provides a broad introduction, as well as for already experienced researchers who may enjoy the exhaustive discussion that covers the research on essentially all currently studied objects and with all available ultrafast pulse sources.
X-Ray Lasers 2016

Author: Tetsuya Kawachi

Publisher: Springer

ISBN: 9783319730257

Category: Science

Page: 421

View: 665

These proceedings comprise a selection of invited and contributed papers presented at the 15th International Conference on X-Ray Lasers (ICXRL 2016), held at the Nara Kasugano International Forum, Japan, from May 22 to 27, 2016. This conference was part of an ongoing series dedicated to recent developments in the science and technology of x-ray lasers and other coherent x-ray sources with additional focus on supporting technologies, instrumentation and applications. The book showcases recent advances in the generation of intense, coherent x-rays, the development of practical devices and their applications across a wide variety of fields. It also discusses emerging topics such as plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generations, as well as other x-ray generation schemes.
Advances in Atomic, Molecular, and Optical Physics

Author: Susanne F. Yelin

Publisher: Academic Press

ISBN: 9780128209882

Category: Science

Page: 314

View: 835

Advances in Atomic, Molecular, and Optical Physics, Volume 69, the latest release in this ongoing series, provides a comprehensive compilation of recent developments in a field that is in a state of rapid growth, as new experimental and theoretical techniques are used on many problems, both old and new. Topics covered in this new release include Strong-field ion spectroscopy, Configurable microscopic optical potentials, Polaritons, Rydberg excitation of trapped cold ions - a new platform for quantum technologies, High intensity QED, Recollision imaging, and more. Presents the work of international experts in the field Contains comprehensive articles that compile recent developments in a field that is experiencing rapid growth, with new experimental and theoretical techniques emerging Ideal for users interested in optics, excitons, plasmas and thermodynamics Covers atmospheric science, astrophysics, and surface and laser physics, amongst other topics
Theory of Nonlinear Propagation of High Harmonics Generated in a Gaseous Medium

Author: Cheng Jin

Publisher: Springer Science & Business Media

ISBN: 9783319016252

Category: Science

Page: 159

View: 230

Theory of Nonlinear Propagation of High Harmonics Generated in a Gaseous Medium establishes the theoretical tools to study High-Order Harmonic Generation (HHG) by intense ultrafast infrared lasers in atoms and molecules. The macroscopic propagation of both laser and high-harmonic fields is taken into account by solving Maxwell's wave equations, while the single-atom or single-molecule response is treated with a quantitative rescattering theory by solving the time-dependent Schrödinger equation. This book demonstrates for the first time that observed experimental HHG spectra of atoms and molecules can be accurately reproduced theoretically when precise experimental conditions are known. The macroscopic HHG can be expressed as a product of a macroscopic wave packet and a photorecombination cross section, where the former depends on laser and experimental conditions while the latter is the property of target atoms or molecules. The factorization makes it possible to retrieve microscopically atomic or molecular structure information from the measured macroscopic HHG spectra. This book also investigates other important issues about HHG, such as contributions from multiple molecular orbitals, the minimum in the HHG spectrum, the spatial mode of laser beams, and the generation of an isolated attosecond pulse. Additionally, this book presents the photoelectron angular distribution of aligned molecules ionized by the HHG light.