Alignment-dependent strong-field ionization yields of carbonyl sulfide molecules induced by mid-infrared laser pulses

Johansen, Rasmus R.; Bay, Kathrine Glerup; Christensen, Lars Rune; Thøgersen, Jan; Dimitrovski, Darko; Madsen, Lars Bojer; Stapelfeldt, Henrik

doi:10.1088/0953-4075/49/20/205601

Cited by 22 publications

(13 citation statements)

References 43 publications

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“…Ionization provides the critical first step in many strong-field processes of current interest, from highharmonic generation and attosecond pulse generation, to laser-induced electron diffraction for time-resolved molecular imaging [1][2][3][4][5][6][7]. For molecules exposed to intense lowfrequency fields, the single and multiple-ionization rates can depend critically on the alignment/orientation of the molecule relative to the direction of the applied field at the instant of ionization [8,[10][11][12][13][14][16][17][18][19][20][21]. Moreover, this relative alignment/orientation influences the degree to which various molecular orbitals contribute to the ionization process and determines the subsequent coherent hole dynamics in the molecular ion.…”

Section: Introductionmentioning

confidence: 99%

“…OCS is a particularly useful molecule for our combined experimental and theoretical studies for several reasons. First, accurate single ionization anisotropy measurements utilizing well-characterized, adiabatically and non-adiabatically aligned molecules are already available for OCS [14,20]. Therefore, we are able to test the accuracy of a new method for extracting ionization yield anisotropies against independent, single ionization measurements.…”

Section: Introductionmentioning

confidence: 99%

“…As alluded to above, strong-field ionization in molecules is a challenging problem for first-principles theory, as it requires a proper description of many-electron correlation effects. From a simulation standpoint, a variety of computational approaches have been applied to angle-dependent ionization rates in molecules [8,9,13,14,[16][17][18][19][20][21]. These range from orbital model-based approaches like molecular-orbital Ammosov-Delone-Krainov (MO-ADK) [22][23][24] and weak-field asymptotic theory [25][26][27][28], to first-principles methods such as time-dependent Hartree-Fock (TDHF) [29][30][31], timedependent density functional theory (TDDFT) [32][33][34][35][36][37][38][39][40][41][42][43][44], and time-dependent configuration-interaction singles (TD-CIS) [45][46][47].…”

Section: Introductionmentioning

confidence: 99%

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Angle dependence of strong-field single and double ionization of carbonyl sulfide

et al. 2018

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We have studied, experimentally and theoretically, the ionization probability of carbonyl sulfide (OCS) molecules in intense linearly-polarized 800 nm laser pulses as a function of the angle between the molecular axis and the laser polarization. Experimentally, the molecules are exposed to two laser pulses with a relative time delay. The first, weaker pulse induces a nuclear rotational wave packet within each molecule such that the ensemble exhibits preferential alignment in the laboratory frame at specific times. The second, stronger pulse induces ionization, and the variation in single and double ionization yields is measured as a function of the delay between the two pulses. The angular-dependence of the ionization yield is extracted by fitting the delay-dependent yields to a sum of delay-dependent moments of the rotational wave packet's angular distribution. We compute these same angular-dependent strong-field ionization yields for OCS using time-dependent density functional theory (TDDFT). For the single ionization case, our measurements agree well with TDDFT calculations and with previous experiments. Furthermore, analysis of the simulated one-body density reveals that, when averaged over a laser cycle, the resulting hole is delocalized across the molecule for light polarized perpendicular to the molecular axis, and mostly localized on the sulfur for parallel polarization. This suggests that preferential molecular alignment is a key parameter for controlling charge migration dynamics initiated by strong-field ionization. For double ionization, the agreement between experiment and theory is less compelling, reflecting the substantial challenges of computing double ionization yields using TDDFT methods.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Angle dependence of strong-field single and double ionization of carbonyl sulfide

et al. 2018

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“…In the linearly polarized ω+2ω twocolor experiment reported by Ohmura et al [27], the preferential direction was however from the S atom side (opposite to the case for circularly polarized pulses [93]). The linear Stark effect on intense-field-induced ionization has yet to be fully elucidated [94][95][96][97][98][99][100].…”

Section: Introductionmentioning

confidence: 99%

Manipulation of Multielectron Dynamics of Molecules by Fourier-Synthesized Intense Laser Pulses: Effective Potential Analysis of CO

Ohmura

Katō

et al. 2021

Front. Phys.

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We present a theoretical investigation as to how multielectron dynamics of CO are manipulated by Fourier-synthesized intense laser pulses. The pulses used are assumed to be comprised of harmonics up to the fourth order. The multiconfiguration time-dependent (TD) Hartree-Fock (MCTDHF) method, where the multielectron wavefunction Ψ(t) is expressed as a linear combination of various electron configurations, is employed to simulate the dynamics of CO interacting with Fourier-synthesized pulses. The multielectron nature such as electron correlation is quantified by using our effective potential approach. To begin with, the time-dependent natural orbitals {ϕj(r,t)} which diagonalize the first order reduced density matrix are obtained from Ψ(t), where r is the one-electron coordinate. The effective potentials υjeff(r,t) that determine the dynamics of ϕj(r,t) are then derived from the equations of motion for {ϕj(r,t)}. υjeff(r,t) consists of the one-body part υ1(t) including the interaction with the laser electric field ε(t) and the two-body part υ2,j(t) originating from electron-electron interaction. In this way, the role of electron correlation can be quantified by comparing υjeff(r,t) with those obtained by the TDHF method, where Ψ(t) is approximated by a single Slater determinant. We found a very similar profile in υ5σeff(r,t) of the 5σ highest occupied molecular orbital for both near-infrared one-color (ω) and directionally asymmetric ω+2ω two-color pulses; when ε(t) points from the nucleus C to O, a hump appears in υ5σeff(r,t) only 2 bohrs outward from C. The hump formation, which originates from the field-induced change in υ2,5σ(t) (especially, due to electron correlation), is responsible for preferential electron ejection from the C atom side (experimentally observed anisotropic ionization). A coherent superposition of ω and 2ω fields with an appropriate relative phase thus works as a one-color pulse of which either positive or negative peaks are filtered out. More sophisticated manipulation is possible by adding higher harmonics to a synthesized field. We show that the 5σ orbital can be squeezed toward the inside of the potential valley in υ5σeff(r,t), which encloses the molecule at a radius of ∼7 bohrs (semicircle in the region of z <0), by adjusting the phases of a ω+2ω+3ω+4ω field. The hump and valley formation in υ5σeff(r,t) are closely correlated with domains of increasing and decreasing electron density, respectively.

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“…[18][19][20][21]), molecular alignment and orientation (see, e.g, Refs. [22][23][24][25][26]), isotope effect [27,28], multielectron effects (see, e.g., Refs. [29][30][31][32]), and contribution from multiple orbitals (see, e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Torsional effects in strong-field ionization of molecules

Dnestryan

Tolstikhin

Jensen

et al. 2019

Phys. Rev. Research

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We investigate how the ionization rate of molecules consisting of a pair of phenyl rings depends on the torsional dihedral angle between these two rings. We consider different orientations of the molecules with respect to the external field direction and find differences in the rates in biphenyl and substituted biphenyl. The evaluation of the rates is made possible by application of the integral representation of the weak-field asymptotic theory for tunneling ionization. We report a strong variation of the ionization rates with dihedral angle with contributions from several orbitals and a large difference between biphenyl and substituted biphenyl related to the permanent dipole of the latter system.

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Alignment-dependent strong-field ionization yields of carbonyl sulfide molecules induced by mid-infrared laser pulses

Cited by 22 publications

References 43 publications

Angle dependence of strong-field single and double ionization of carbonyl sulfide

Angle dependence of strong-field single and double ionization of carbonyl sulfide

Manipulation of Multielectron Dynamics of Molecules by Fourier-Synthesized Intense Laser Pulses: Effective Potential Analysis of CO

Torsional effects in strong-field ionization of molecules

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