Laser-induced 3D alignment and orientation of quantum state-selected molecules

Nevo, Iftach; Holmegaard, Lotte; Nielsen, Jens Hedegaard; Hansen, Jonas L.; Stapelfeldt, Henrik; Filsinger, Frank; Meijer, Gerard; Küpper, Jochen

doi:10.1039/b910423b

Cited by 98 publications

(123 citation statements)

References 35 publications

(76 reference statements)

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“…When the 3:1 elliptically polarized YAG pulse, its major polarization axis perpendicular to the detector, is used, the circular symmetry is broken and, instead, the H + ions localize around the vertical axis corresponding to the minor axis of the polarization ellipse. Similarly to previous studies [38,40] we interpret this as confinement of the molecular plane with the second-most polarizable axis (perpendicular to the C 2 axis but still in the molecular plane) aligned along the minor axis of the ellipse. …”

Section: B Alignment and Orientationmentioning

confidence: 93%

“…In particular, we show that ionization of molecules, 1D aligned and oriented with their dipole moment along the direction of F stat , leads to electrons with an upward (downward) momentum for LCP (RCP) probe pulses in agreement with the observations. The observation of an asymmetry without the YAG pulse results from mild orientation due to the interaction between the permanent dipole moment and the weak static field and/or state selection by the deflector [38].…”

Section: Pads From Single Ionization Of Benzonitrilementioning

confidence: 99%

“…Their alignment and orientation are controlled by the combination of the YAG pulse and the weak static electric field in the VMI spectrometer. Based on previous experiments and theory, a linearly polarized YAG pulse is used to induce 1D alignment and orientation, whereas 3D alignment and orientation is created by applying an elliptically polarized YAG pulse [14,21,[35][36][37][38]. Here 1D alignment refers to confinement of a single molecular axis along the YAG polarization axis.…”

Section: B Alignment and Orientationmentioning

confidence: 99%

“…To additionally confirm confinement of the molecular plane H + ions were recorded (see Fig. 4) following an approach employed in previous studies [38,40] of 3D alignment. When the probe laser only is used, the image is circularly symmetric [ Fig.…”

Section: B Alignment and Orientationmentioning

confidence: 99%

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Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses

et al. 2011

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We present a combined experimental and theoretical study on strong-field ionization of a three-dimensionallyoriented asymmetric top molecule, benzonitrile (C 7 H 5 N), by circularly polarized, nonresonant femtosecond laser pulses. Prior to the interaction with the strong field, the molecules are quantum-state selected using a deflector and three-dimensionally (3D) aligned and oriented adiabatically using an elliptically polarized laser pulse in combination with a static electric field. A characteristic splitting in the molecular frame photoelectron momentum distribution reveals the position of the nodal planes of the molecular orbitals from which ionization occurs. The experimental results are supported by a theoretical tunneling model that includes and quantifies the splitting in the momentum distribution. The focus of the present article is to understand strong-field ionization from 3D-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals. In the preceding article [Dimitrovski et al., Phys. Rev. A 83, 023405 (2011)] the focus is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons.

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Section: B Alignment and Orientationmentioning

confidence: 93%

Section: Pads From Single Ionization Of Benzonitrilementioning

confidence: 99%

Section: B Alignment and Orientationmentioning

confidence: 99%

Section: B Alignment and Orientationmentioning

confidence: 99%

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Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses

et al. 2011

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“…3(a) and 3(b)], the electrons emerge in a stripe parallel to the Y ,Z polarization plane of the 2.4 × 10 14 W/cm 2 probe pulse. The images are essentially up-down symmetric and the marginal difference between the images obtained with left and right circularly polarized (LCP and RCP) pulses is due to experimental imperfections in the purity of the polarization state and a weak orientation of the molecules caused by the static field alone [36]. When the molecules are one-dimensionally (1D) aligned along the Y direction, i.e., the molecular axis is confined along the Y axis but with no preferred direction of the dipole moment, not much happens and no up-down asymmetry is observed [Figs.…”

Section: B Pads From Single Ionization Of Ocsmentioning

confidence: 99%

Ionization of oriented carbonyl sulfide molecules by intense circularly polarized laser pulses

et al. 2011

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We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl sulfide molecules by circularly polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation. The focus of the present article is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons. In the following article [Phys. Rev. A 83, 023406 (2011)] the focus is to understand strong-field ionization from three-dimensionally-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals.

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Manipulating the Motion of Complex Molecules: Deflection, Focusing, and Deceleration of Molecular Beams for Quantum‐State and Conformer Selection

Küpper

Filsinger

Meijer

et al. 2012

Methods in Physical Chemistry

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Method summary Acronyms• effective dipole moment (µ eff )• low-field seeking (lfs) state• high-field seeking (hfs) state • Alternating gradient (AG) focusing• photo-multiplier tube (PMT)• transition state (TS) Strengths of technique• allows to spatially separate molecules in different quantum states, including isomers of complex molecules• versatile -DC field techniques can be applied to all polar molecules, AC field techniques to all polarizable molecules (= all molecules)• quantum-state specific interaction -can, in principle, be used to separate all kinds of isomers• determination of rotational, vibrational, and electronic properties -including dipole moments and polarizabilities -of single isomers of complex molecules• allows for detailed investigations of stereochemical dynamics• allows to separate molecular ensembles from seedgas, avoiding background in various scattering experiments Limitations• translations of non-polar molecules can -for practical purposes -not be manipulated by dc electric fields• no ultracold samples (µK or below) produced so far * This chapter is largely based on parts of reference 1. † Email: jochen.kuepper@cfel.de 1 2 Controlled moleculesChemists have long been dreaming of ultimately controlling all aspects of chemical reactions. Empirically, vast progress has been made over the last centuries using increasingly sophisticated techniques to dictate the path and outcome of chemical reactions. However, in all these approaches external parameters are used to (classically) shift statistical outcomes one way or another. Recently, the field of cold and ultracold chemistry has started to provide a glimpse at a new level of control, where full quantum-mechanical control can be obtained. So far this has been demonstrated for very specific small reactions systems, i. e., for reactions of alkali dimers with alkali atoms 2,3 or with each other, including the observation of stereochemical effects. 4 In these experiments molecules are prepared at low temperatures and specific quantum states starting from ultracold ensembles oftypically alkali -atoms, which is the limiting factor to the possible complexity and versatility of these methods. Alternatively, cold collisions of small molecules, i. e., OH radicals, with rare gas atoms at arbitrarily low collision energies have been investigated. 5,6 In this chapter we will present the available methods to gain control over the motion and the quantum-state populations over complex molecules (albeit at a lower level). These methods could enable a new level of detail in the study and control of chemical reactions for a large variety of molecules. Moreover, the prepared samples of controlled molecules are useful in a wide variety of experiments, ranging from the taking of actual photographs of the molecules -and their inherent or induced dynamics -using ultrafast X-ray or electron diffraction over, for example, photoelectron distributions and high-harmonic generation to investigations of attosecond electron dynamics and charge migration. 7 These experiments...

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Laser-induced 3D alignment and orientation of quantum state-selected molecules

Cited by 98 publications

References 35 publications

Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses

Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses

Ionization of oriented carbonyl sulfide molecules by intense circularly polarized laser pulses

Manipulating the Motion of Complex Molecules: Deflection, Focusing, and Deceleration of Molecular Beams for Quantum‐State and Conformer Selection

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