1
|
Yang L, Reimers JR, Kobayashi R, Hush NS. Competition between charge migration and charge transfer induced by nuclear motion following core ionization: Model systems and application to Li 2. J Chem Phys 2019; 151:124108. [PMID: 31575213 DOI: 10.1063/1.5117246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Attosecond and femtosecond spectroscopies present opportunities for the control of chemical reaction dynamics and products, as well as for quantum information processing; we address the somewhat unique situation of core-ionization spectroscopy which, for dimeric chromophores, leads to strong valence charge localization and hence tightly paired potential-energy surfaces of very similar shape. Application is made to the quantum dynamics of core-ionized Li2 +. This system is chosen as Li2 is the simplest stable molecule facilitating both core ionization and valence ionization. First, the quantum dynamics of some model surfaces are considered, with the surprising result that subtle differences in shape between core-ionization paired surfaces can lead to dramatic differences in the interplay between electronic charge migration and charge transfer induced by nuclear motion. Then, equation-of-motion coupled-cluster calculations are applied to determine potential-energy surfaces for 8 core-excited state pairs, calculations believed to be the first of their type for other than the lowest-energy core-ionized molecular pair. While known results for the lowest-energy pair suggest that Li2 + is unsuitable for studying charge migration, higher-energy pairs are predicted to yield results showing competition between charge migration and charge transfer. Central is a focus on the application of Hush's 1975 theory for core-ionized X-ray photoelectron spectroscopy to understand the shapes of the potential-energy surfaces and hence predict key features of charge migration.
Collapse
Affiliation(s)
- Likun Yang
- International Centre for Quantum and Molecular Structures and Department of Physics, Shanghai University, Shanghai 200444, China
| | - Jeffrey R Reimers
- School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Rika Kobayashi
- International Centre for Quantum and Molecular Structures and Department of Physics, Shanghai University, Shanghai 200444, China
| | - Noel S Hush
- School of Molecular Biosciences, The University of Sydney, Sydney, NSW 2006, Australia
| |
Collapse
|
2
|
Talukder S, Sen S, Shandilya BK, Sharma R, Chaudhury P, Adhikari S. Enhancing the branching ratios in the dissociation channels for O(16)O(16)O(18) molecule by designing optimum laser pulses: A study using stochastic optimization. J Chem Phys 2015; 143:144109. [PMID: 26472365 DOI: 10.1063/1.4932333] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We propose a strategy of using a stochastic optimization technique, namely, simulated annealing to design optimum laser pulses (both IR and UV) to achieve greater fluxes along the two dissociating channels (O(18) + O(16)O(16) and O(16) + O(16)O(18)) in O(16)O(16)O(18) molecule. We show that the integrated fluxes obtained along the targeted dissociating channel is larger with the optimized pulse than with the unoptimized one. The flux ratios are also more impressive with the optimized pulse than with the unoptimized one. We also look at the evolution contours of the wavefunctions along the two channels with time after the actions of both the IR and UV pulses and compare the profiles for unoptimized (initial) and optimized fields for better understanding the results that we achieve. We also report the pulse parameters obtained as well as the final shapes they take.
Collapse
Affiliation(s)
- Srijeeta Talukder
- Department of Chemistry, University of Calcutta, 92 A P C Road, Kolkata 700 009, India
| | - Shrabani Sen
- Department of Chemistry, Rammohan College, 102/1, Raja Rammohan Sarani, Kolkata 700 009, India
| | - Bhavesh K Shandilya
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
| | - Rahul Sharma
- Department of Chemistry, St. Xavier's College, 30 Mother Teresa Sarani, Kolkata 700 016, India
| | - Pinaki Chaudhury
- Department of Chemistry, University of Calcutta, 92 A P C Road, Kolkata 700 009, India
| | - Satrajit Adhikari
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| |
Collapse
|
3
|
Biggs JD, Cina JA. Using wave-packet interferometry to monitor the external vibrational control of electronic excitation transfer. J Chem Phys 2010; 131:224101. [PMID: 20001018 DOI: 10.1063/1.3257596] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the control of electronic energy transfer in molecular dimers through the preparation of specific vibrational coherences prior to electronic excitation, and its observation by nonlinear wave-packet interferometry (nl-WPI). Laser-driven coherent nuclear motion can affect the instantaneous resonance between site-excited electronic states and thereby influence short-time electronic excitation transfer (EET). We first illustrate this control mechanism with calculations on a dimer whose constituent monomers undergo harmonic vibrations. We then consider the use of nl-WPI experiments to monitor the nuclear dynamics accompanying EET in general dimer complexes following impulsive vibrational excitation by a subresonant control pulse (or control pulse sequence). In measurements of this kind, two pairs of polarized phase-related femtosecond pulses following the control pulse generate superpositions of coherent nuclear wave packets in optically accessible electronic states. Interference contributions to the time- and frequency-integrated fluorescence signals due to overlaps among the superposed wave packets provide amplitude-level information on the nuclear and electronic dynamics. We derive the basic expression for a control-pulse-dependent nl-WPI signal. The electronic transition moments of the constituent monomers are assumed to have a fixed relative orientation, while the overall orientation of the complex is distributed isotropically. We include the limiting case of coincident arrival by pulses within each phase-related pair in which control-influenced nl-WPI reduces to a fluorescence-detected pump-probe difference experiment. Numerical calculations of pump-probe signals based on these theoretical expressions are presented in the following paper [J. D. Biggs and J. A. Cina, J. Chem. Phys. 131, 224302 (2009)].
Collapse
Affiliation(s)
- Jason D Biggs
- Department of Chemistry and Oregon Center for Optics, University of Oregon, Eugene, Oregon 97403, USA
| | | |
Collapse
|
4
|
Amitay Z, Gandman A, Chuntonov L, Rybak L. Multichannel selective femtosecond coherent control based on symmetry properties. PHYSICAL REVIEW LETTERS 2008; 100:193002. [PMID: 18518449 DOI: 10.1103/physrevlett.100.193002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Indexed: 05/26/2023]
Abstract
We present and implement a new scheme for extended multichannel selective femtosecond coherent control based on symmetry properties of the excitation channels. Here, an atomic nonresonant two-photon absorption channel is coherently incorporated in a resonance-mediated (2+1) three-photon absorption channel. By proper pulse shaping, utilizing the invariance of the two-photon absorption to specific phase transformations of the pulse, the three-photon absorption is tuned independently over an order-of-magnitude yield range for any possible two-photon absorption yield. Noticeable is a set of "two-photon dark pulses" inducing widely tunable three-photon absorption.
Collapse
Affiliation(s)
- Zohar Amitay
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel.
| | | | | | | |
Collapse
|
5
|
Teranishi Y. Quantum-control spectroscopy with exact state selectivity. PHYSICAL REVIEW LETTERS 2006; 97:053001. [PMID: 17026097 DOI: 10.1103/physrevlett.97.053001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Indexed: 05/12/2023]
Abstract
A method of exact state-selective spectroscopy is introduced, based on quantum control through four specific short laser pulses. The exact conditions for the two pairs of ultrafast pulses are set by the feedback control for selective excitation to one specific resonance state while the other state is destructively interfered as the shadow pair, leading to a state-selective spectrum.
Collapse
Affiliation(s)
- Yoshiaki Teranishi
- Advanced Photon Research Center, Japan Atomic Energy Research Institute, Kizu-cho, Kyoto 619-0215, Japan
| |
Collapse
|
6
|
Lozovoy VV, Dantus M. Systematic Control of Nonlinear Optical Processes Using Optimally Shaped Femtosecond Pulses. Chemphyschem 2005; 6:1970-2000. [PMID: 16208734 DOI: 10.1002/cphc.200400342] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This article reviews experimental efforts to control multiphoton transitions using shaped femtosecond laser pulses, and it lays out the systematic study being followed by us for elucidating the effect of phase on nonlinear optical laser-molecule interactions. Starting with a brief review of nonlinear optics and how nonlinear optical processes depend on the electric field inducing them, a number of conclusions can be drawn directly from analytical solutions of the equations. From a Taylor expansion of the phase in the frequency domain, we learn that nonlinear optical processes are affected only by the second- and higher-order terms. This simple result has significant implications on how pulse-shaping experiments are to be designed. If the phase is allowed to vary arbitrarily as a continuous function, then an infinite redundancy that arises from the addition of a linear phase function across the spectrum with arbitrary offset and slope could prevent us from carrying out a closed-loop optimization experiment. The early results illustrate how the outcome of a nonlinear optical transition depends on the cooperative action of all frequencies in the bandwidth of a laser pulse. Maximum constructive or destructive interference can be achieved by programming the phase using only two phase values, 0 and pi. This assertion has been confirmed experimentally, where binary phase shaping (BPS) was shown to outperform other alternative functions, sometimes by at least on order of magnitude, in controlling multiphoton processes. Here we discuss the solution of a number of nonlinear problems that range from narrowing the second harmonic spectrum of a laser pulse to optimizing the competition between two- and three-photon transitions. This Review explores some present and future applications of pulse shaping and coherent control.
Collapse
Affiliation(s)
- Vadim V Lozovoy
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | | |
Collapse
|
7
|
Abstract
This critical review is intended to provide an overview of the state-of-the-art in femtosecond laser technology and recent applications in ultrafast gas phase chemical dynamics. Although "femtochemistry" is not a new subject, there have been some tremendous advances in experimental techniques during the last few years. Time-resolved photoelectron spectroscopy and ultrafast electron diffraction have enabled us to observe molecular dynamics through a wider window. Attosecond laser sources, which have so far only been exploited in atomic physics, have the potential to probe chemical dynamics on an even faster timescale and observe the motions of electrons. Huge progress in pulse shaping and pulse characterisation methodology is paving the way for exciting new advances in the field of coherent control.
Collapse
Affiliation(s)
- R E Carley
- Department of Chemistry, University College London, London WC1H 0AJ, UK
| | | | | |
Collapse
|
8
|
Bonacić-Koutecký V, Mitrić R. Theoretical Exploration of Ultrafast Dynamics in Atomic Clusters: Analysis and Control. Chem Rev 2004; 105:11-66. [PMID: 15720151 DOI: 10.1021/cr0206925] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vlasta Bonacić-Koutecký
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, D-12489 Berlin, Germany.
| | | |
Collapse
|
9
|
Yokoyama K, Teranishi Y, Toya Y, Shirai T, Fukuda Y, Aoyama M, Akahane Y, Inoue N, Ueda H, Yamakawa K, Yokoyama A, Yamada H, Yabushita A, Sugita A. Optimal control of ultrafast selection. J Chem Phys 2004; 120:9446-9. [PMID: 15267954 DOI: 10.1063/1.1752882] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Optimal laser control for ultrafast selection of closely lying excited states whose energy separation is smaller than the laser bandwidth is reported on the two-photon transition of atomic cesium; Cs(6S-->7D(J), J=5/2 and 3/2). Selective excitation was carried out by pulse shaping of ultrashort laser pulses which were adaptively modulated in a closed-loop learning system handling eight parameters representing the electric field. Two-color fluorescence from the respective excited states was monitored to measure the selectivity. The fitness used in the learning algorithm was evaluated from the ratio of the fluorescence yields. After fifty generations, a pair of nearly transform-limited pulses were obtained as an optimal pulse shape, proving the effectiveness of the "Ramsey fringes" mechanism. The contrast of the selection ratio was improved by approximately 30% from the simple "Ramsey fringes" experiment.
Collapse
Affiliation(s)
- K Yokoyama
- Advanced Photon Research Center, Japan Atomic Energy Research Institute, Kizu-cho, Kyoto 619-0215, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Schäfer-Bung B, Mitrić R, Bonačić-Koutecký V, Bartelt A, Lupulescu C, Lindinger A, Vajda Š, Weber SM, Wöste L. Optimal Control of Ionization Processes in NaK: Comparison between Theory and Experiment. J Phys Chem A 2004. [DOI: 10.1021/jp049153p] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Dantus M, Lozovoy VV. Experimental Coherent Laser Control of Physicochemical Processes. Chem Rev 2004; 104:1813-59. [PMID: 15080713 DOI: 10.1021/cr020668r] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marcos Dantus
- Department of Chemistry and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
| | | |
Collapse
|
12
|
Lozovoy VV, Pastirk I, Walowicz KA, Dantus M. Multiphoton intrapulse interference. II. Control of two- and three-photon laser induced fluorescence with shaped pulses. J Chem Phys 2003. [DOI: 10.1063/1.1531620] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
13
|
Mirowski E, Stauffer HU, Ballard JB, Zhang B, Hetherington CL, Leone SR. Effect of nonresonant frequencies on the enhancement of quantum beat amplitudes in rovibrational states of Li2: The role of state spacing. J Chem Phys 2002. [DOI: 10.1063/1.1522717] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
14
|
Degert J, Wohlleben W, Chatel B, Motzkus M, Girard B. Realization of a time-domain Fresnel lens with coherent control. PHYSICAL REVIEW LETTERS 2002; 89:203003. [PMID: 12443475 DOI: 10.1103/physrevlett.89.203003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2002] [Indexed: 05/24/2023]
Abstract
Perturbative chirped pulse excitation leads to oscillations of the excited state amplitude. These coherent transients are governed by interferences between resonant and off-resonant contributions. Control mechanisms in both frequency and time domain are used to modify these dynamics. First, by applying a phase step in the spectrum, we manipulate the phase of the oscillations. By direct analogy with Fresnel zone lenses, we then conceive highly phase-amplitude modulated pulse shapes that slice destructive interferences out of the excitation time structure and enhance the final population.
Collapse
Affiliation(s)
- Jérôme Degert
- Laboratoire de Collisions, Agrégats, Réactivité (CNRS UMR 5589), IRSAMC, Université Paul Sabatier, 31062 Toulouse, France
| | | | | | | | | |
Collapse
|