Control of bond-selective photochemistry in CH $\scriptstyle \mathsf {2}$ BrCl using adaptive femtosecond pulse shaping

Damrauer, Niels H.; Dietl, Christian; Krampert, Gerhard; Lee, S.-H.; Jung, Kwangyun; Gerber, G.

doi:10.1140/epjd/e2002-00101-8

Cited by 76 publications

(46 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Optimal control experiments (OCE) employing closed-loop learning control 1 have found success in a wide range of applications, 2 including high harmonic generation, [3][4][5] bond-breaking in molecules, [6][7][8][9][10] and energy transfer in biomolecules. 11 Simulations employing optimal control theory have achieved high yields in large numbers of quantum systems.…”

Section: Introductionmentioning

confidence: 99%

Exploring constrained quantum control landscapes

Moore

Rabitz

2012

The Journal of Chemical Physics

123

View full text Add to dashboard Cite

The broad success of optimally controlling quantum systems with external fields has been attributed to the favorable topology of the underlying control landscape, where the landscape is the physical observable as a function of the controls. The control landscape can be shown to contain no suboptimal trapping extrema upon satisfaction of reasonable physical assumptions, but this topological analysis does not hold when significant constraints are placed on the control resources. This work employs simulations to explore the topology and features of the control landscape for pure-state population transfer with a constrained class of control fields. The fields are parameterized in terms of a set of uniformly spaced spectral frequencies, with the associated phases acting as the controls. This restricted family of fields provides a simple illustration for assessing the impact of constraints upon seeking optimal control. Optimization results reveal that the minimum number of phase controls necessary to assure a high yield in the target state has a special dependence on the number of accessible energy levels in the quantum system, revealed from an analysis of the first- and second-order variation of the yield with respect to the controls. When an insufficient number of controls and/or a weak control fluence are employed, trapping extrema and saddle points are observed on the landscape. When the control resources are sufficiently flexible, solutions producing the globally maximal yield are found to form connected "level sets" of continuously variable control fields that preserve the yield. These optimal yield level sets are found to shrink to isolated points on the top of the landscape as the control field fluence is decreased, and further reduction of the fluence turns these points into suboptimal trapping extrema on the landscape. Although constrained control fields can come in many forms beyond the cases explored here, the behavior found in this paper is illustrative of the impacts that constraints can introduce.

show abstract

Section: Introductionmentioning

confidence: 99%

Exploring constrained quantum control landscapes

Moore

Rabitz

2012

The Journal of Chemical Physics

123

View full text Add to dashboard Cite

show abstract

“…As the temporal profile and all other laser parameters can be tuned in an extremely flexible manner, the question naturally arises whether one could tune laser pulses for maximum yield (or other desired reaction ) -39 properties). This is the idea of ''optimal control'' which is of particular importance in chemistry and molecular physics, see e.g., [171,172]. Again, the application to large clusters is more involved and allows more strategies to be tracked.…”

Section: Pump and Probe (Pandp) Analysis Of Ionic Dynamicsmentioning

confidence: 99%

Electrons as probes of dynamics in molecules and clusters: A contribution from Time Dependent Density Functional Theory

et al. 2015

View full text Add to dashboard Cite

a b s t r a c tThere are various ways to analyze the dynamical response of clusters and molecules to electromagnetic perturbations. Particularly rich information can be obtained from measuring the properties of electrons emitted in the course of the excitation dynamics. Such an analysis of electron signals covers observables such as total ionization, PhotoElectron Spectra (PES), Photoelectron Angular Distributions (PAD), and ideally combined PES/PAD. It has a long history in molecular physics and was increasingly used in cluster physics as well. Recent progress in the design of new light sources (high intensity, high frequency, ultra short pulses) opens new possibilities for measurements and thus has renewed the interest on these observables, especially for the analysis of various dynamical scenarios, well beyond a simple access to electronic density of states. This, in turn, has motivated many theoretical investigations of the dynamics of electronic emission for molecules and clusters up to such a complex and interesting system as C 60 . A theoretical tool of choice is here Time-Dependent Density Functional Theory (TDDFT) propagated in real time and on a spatial grid, and augmented by a Self-Interaction Correction (SIC). This provides a pertinent, robust, and efficient description of electronic emission including the detailed pattern of PES and PAD. A direct comparison between experiments and well founded elaborate microscopic theories is thus readily possible, at variance with more demanding observables such as for example fragmentation or dissociation cross sections.The purpose of this paper is to describe the theoretical tools developed on the basis of real-time and real-space TDDFT and to address in a realistic manner the analysis of electronic emission following irradiation of clusters and molecules by various laser pulses. After a general introduction, we shall present in a second part the available experimental results motivating such studies, starting from the simplest total ionization signals to the more elaborate PES and PAD, possibly combining them and/or resolving them in time. This experimental discussion will be complemented in a third part by a presentation of available theoretical tools focusing on TDDFT and detailing the methods used to address ionization observables. We shall also discuss the shortcomings of standard versions of TDDFT, especially what concerns the SIC problem, and show how to improve formally and practically the theory on that aspect. A long fourth part will be devoted to representative * P. Wopperer et al. / Physics Reports ( ) -results. We shall illustrate the use of total ionization in pump and probe scenarios with fs lasers for tracking ionic dynamics in clusters. More challenging from the experimental point of view is pump and probe setups using attosecond pulses. The effort there is more on the capability to define proper signals to be measured/computed at such a short time scale. TDDFT analysis provides here a valuable tool in the search for the most efficient observab...

show abstract

“…Among the first demonstrations of this method were the optimization of the excited state population of a laser dye by Bardeen et al [45] and the automated compression of femtosecond laser pulses [44,[46][47][48]. Since then, the dissociation of molecules in the gas phase [49][50][51][52], energy transfer in large biomolecular molecules [53], selective excitation of different vibrational modes [54,55] and the control of the geometrical rearrangement in the liquid phase [56] and many other problems have been successfully controlled.…”

Section: Adaptive Quantum Controlmentioning

confidence: 99%