High-order harmonic generation in vibrating two-electron molecules

Chirilă, C. C.; Lein, Manfred

doi:10.1016/j.chemphys.2009.09.004

Cited by 8 publications

(10 citation statements)

References 41 publications

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“…Evaluation of the nonadiabatic matrix elements ⟨m|gĵ i (1) |n⟩ (eq 11) requires some special attention. The derivative with respect to q s does not present a problem because (35) where E i is the energy of an adiabatic electronic state i at the origin and g i is its gradient with respect to q. When (E i − E j )is large compared to ℏ 1/2 (g i − g j )·ω −1/2 (in other words, when the state intersection is far away compared to a typical extent of a nuclear basis function), the denominator in eq 34 can be expanded in a Taylor series truncated at a suitably low order (we choose O(q 1 ) to remain consistent with the quadratic expansion of the PES).…”

Section: ■ Computational Detailsmentioning

confidence: 99%

“…Permanent dipoles d ii describe the linear Stark shift of the electronic surfaces, while the transition dipoles d ij (j ≠ i) are responsible for the fieldinduced population transfer between the surfaces. 35 While it is possible to propagate eq 8 numerically, at short times, it seems natural to develop an analytical expression for the amplitudes a in by expanding them in a power series of time …”

Section: ■ Theorymentioning

confidence: 99%

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Short-Time Dynamics at a Conical Intersection in High-Harmonic Spectroscopy

Patchkovskii

Schuurman

2014

J. Phys. Chem. A

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur.Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Short-time dynamics at a conical intersection in high-harmonic spectroscopy Patchkovskii, Serguei; Schuurman, Michael S.http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/droits L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=aad3fd82-4d1b-46b5-8a04-31cbd7427a52 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=aad3fd82-4d1b-46b5-8a04-31cbd7427a52 ABSTRACT: High-harmonic spectroscopy probes molecular dynamics using electrons liberated from the same molecule earlier in the laser cycle. It affords sub-Ångstrom spatial and subfemtosecond temporal resolution. Nuclear dynamics in the intermediate cation influence the spectrum of the emitted high-harmonic photons through an autocorrelation function. Here, we develop an analytical approach for computing short-time nuclear autocorrelation functions in the vicinity of conical intersections, including laser-induced and nonadiabatic coupling between the surfaces. We apply the technique to two molecules of current experimental interest, C 6 H 6 and C 6 H 5 F. In both molecules, high-harmonics generated within the same electronic channel are not sensitive to nonadiabatic dynamics, even in the presence of substantial population transfer. Calculated autocorrelation functions exhibit significant deviations from the expected Gaussian decay and may undergo revivals at short (∼1.5 fs) times. The associated phase of the nuclear wavepacket provides a possible experimental signature.

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Section: ■ Computational Detailsmentioning

confidence: 99%

Section: ■ Theorymentioning

confidence: 99%

Short-Time Dynamics at a Conical Intersection in High-Harmonic Spectroscopy

Patchkovskii

Schuurman

2014

J. Phys. Chem. A

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“…However, the first half revival occurs at an earlier time, and has a substantially higher magnitude (CH 4 : 2.9/2.5% at 1.93/1.98 fs for ν 4 /ν 3 ; CD 4 : 2.8/2.7% at 2.23/2.25 fs for ν 4 /ν 3 respectively). The faster short-time dynamics of vibrationally excited states has been noted before [52,65,67,85,94]. This property will be important for understanding the HHG spectra at longer wavelengths (Sec.…”

Section: A Free-cation Dynamics and Autocorrelation Functionmentioning

confidence: 99%

“…Nonetheless, most of the non-BO numerical studies of HHG still concern the dynamics of simple, oneand two-electron diatomics (H 2 [65][66][67][68], H 2 + [64,66,[68][69][70][71][72][73][74][75][76][77][78][79][80], HeH 2+ [81]), usually with the additional approximations of the reduced dimensionality [66][67][68][69][70][71][72][73][74]77,80,81] or special field polarizations [64,75,76,78,79]. Some attempts at extending the theory of nuclear dynamics in HHG to more general non-BO systems have been reported in the literature [65,[82][83][84][85][86][87][88][89][90][91]…”

Section: Published By the American Physical Society Under The Terms Omentioning

confidence: 99%

Full-dimensional treatment of short-time vibronic dynamics in a molecular high-order-harmonic-generation process in methane

Patchkovskii

Schuurman

2017

Phys. Rev. A

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We present derivation and implementation of the multiconfigurational strong-field approximation with Gaussian nuclear wave packets (MC-SFA-GWP)-a version of the molecular strong-field approximation which treats all electronic and nuclear degrees of freedom, including their correlations, quantum mechanically. The technique allows realistic simulation of high-order-harmonic emission in polyatomic molecules without invoking reduced-dimensionality models for the nuclear motion or the electronic structure. We use MC-SFA-GWP to model isotope effects in high-order-harmonic-generation (HHG) spectroscopy of methane. The HHG emission in this molecule transiently involves the strongly vibronically coupled 2 F 2 electronic state of the CH 4 + cation. We show that the isotopic HHG ratio in methane contains signatures of (a) field-free vibronic dynamics at the conical intersection (CI); (b) resonant features in the recombination cross sections; (c) laser-driven bound-state dynamics; as well as (d) the well-known short-time Gaussian decay of the emission. We assign the intrinsic vibronic feature (a) to a relatively long-lived ( 4 fs) vibronic wave packet of the singly excited ν 4 (t 2 ) and ν 2 (e) vibrational modes, strongly coupled to the components of the 2 F 2 electronic state. We demonstrate that these physical effects differ in their dependence on the wavelength, intensity, and duration of the driving pulse, allowing them to be disentangled. We thus show that HHG spectroscopy provides a versatile tool for exploring both conical intersections and resonant features in photorecombination matrix elements in the regime not easily accessible with other techniques.

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“…Thorough theoretical studies [135][136][137][138] and CD 4 [74,140], which measured the relative harmonic intensities for each pair. The interpretation of the HHG as a pump-probe scheme, where ionization is represented as a pump and the recombination as a probe, is exploited in these studies: each harmonic via its amplitude, polarization and phase contains information about the nuclear dynamics of the molecule.…”

Section: Nuclear Dynamics Via Hhgmentioning

confidence: 99%

Multidimensional high harmonic spectroscopy

Serbinenko

Smirnova

2013

2013 Conference on Lasers &Amp; Electro-Optics Europe &Amp; International Quantum Electronics Conference CLEO EUROPE/IQEC

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Multidimensional high harmonic spectroscopy is a cutting-edge technique for studying the effect of the intense low-frequency laser fields on atoms and molecules. The high energy photons, emitted by a particle as a result of the interaction with the strong laser field, carry the information about the processes in atoms and molecules, which lead to the emission. Multidimensional character of the technique allows to extract parameters of the molecular and atomic ionization dynamics, that were inaccessible before in the same experiment, such as sub-cycle ionization rates, ionization and recombination times.The Thesis presents in detail theoretical analysis of the multidimensional high harmonic generation process within semi-classical approach. Several generating field configurations are considered. The developed theoretical apparatus is then applied to describe multidimensional high harmonic spectroscopy experiments in helium. Initial analysis of the applicability of the technique for the study of multielectron dynamics in carbon dioxide is also performed.The problems, solutions to which are presented in the Thesis, are:• theoretical description of high harmonic generation in multicolor fields• analysis of the gating techniques for the extraction of the parameters of electron trajectories in high harmonic generation in He• proposition of an alternative reconstruction procedure of electron trajectory parameters, that allows one to access to all of them simultaneouslyThe main results of our work are:• Based on theoretical analysis of multidimensional high harmonic generation, we showed, that optimization of the two-dimensional harmonic 3 signal is achieved at each step of the process: ionization, propagation, dynamics in the ion and recombination• We demonstrated, that multidimensional high harmonic spectroscopy is a very sensitive tool allowing one to extract parameters of electron trajectories, such as complex ionization time and complex electron momentum, from the observed harmonic signal• We developed and applied theory to the analysis of two-color high harmonic generation experiments of He atom• We performed initial analysis of two-color HHG experiments in carbon dioxide, which was necessary for further investigation and reconstruction I thank Bettina Becker, the most helpful person in the institute or in the whole world, who made the bureaucratic problems very easy. There was no question she didn't answer and no problem she didn't solve quickly and efficiently.

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High-order harmonic generation in vibrating two-electron molecules

Cited by 8 publications

References 41 publications

Short-Time Dynamics at a Conical Intersection in High-Harmonic Spectroscopy

Short-Time Dynamics at a Conical Intersection in High-Harmonic Spectroscopy

Full-dimensional treatment of short-time vibronic dynamics in a molecular high-order-harmonic-generation process in methane

Multidimensional high harmonic spectroscopy

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