Strong field ionization of linear molecules: a correlated three-dimensional calculation

Jordan, Gerald; Caillat, Jérémie; Ede, Christopher; Scrinzi, Armin

doi:10.1088/0953-4075/39/13/s07

Cited by 40 publications

(38 citation statements)

References 20 publications

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“…These characteristics should be the key in the three-dimensional (3D) multielectron dynamics, where the existence of energetically closely-lying valence electrons is quite common, which requires to take both multichannel and multielectron effects into account. As discussed previously [62], cares have to be made for the physical soundness of 1D models. Nevertheless, we expect that the features (i) and (ii) are transferable, and 1D applications can elucidate advantages and limitations of theoretical methods, before applied to real 3D systems.…”

Section: A 1d-lih and Lih Dimer Models: Ground-statementioning

confidence: 99%

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Time-dependent complete-active-space self-consistent-field method for multielectron dynamics in intense laser fields

2013

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The time-dependent complete-active-space self-consistent-field (TD-CASSCF) method for the description of multielectron dynamics in intense laser fields is presented, and a comprehensive description of the method is given. It introduces the concept of frozen-core (to model tightly bound electrons with no response to the field), dynamical-core (to model electrons tightly bound but responding to the field), and active (fully correlated to describe ionizing electrons) orbital subspaces, allowing compact yet accurate representation of ionization dynamics in many-electron systems. The classification into the subspaces can be done flexibly, according to simulated physical situations and desired accuracy, and the multiconfiguration time-dependent Hartree-Fock (MCTDHF) approach is included as a special case. To assess its performance, we apply the TD-CASSCF method to the ionization dynamics of one-dimensional lithium hydride (LiH) and LiH dimer models, and confirm that the present method closely reproduces rigorous MCTDHF results if active orbital space is chosen large enough to include appreciably ionizing electrons. The TD-CASSCF method will open a way to the first-principle theoretical study of intense-field induced ultrafast phenomena in realistic atoms and molecules.PACS numbers: 32.80. Rm, 42.65.Ky

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Section: A 1d-lih and Lih Dimer Models: Ground-statementioning

confidence: 99%

“…See also Refs. [60][61][62][63][64][65][66] for the MCTDHF method, and Beck et al [67] and references therein for the precedent multiconfiguration time-dependent Hartree method for Bosons. Despite its naming, which in principle refers to the general multiconfiguration wavefunction of the form Eq.…”

mentioning

confidence: 99%

Time-dependent complete-active-space self-consistent-field method for multielectron dynamics in intense laser fields

2013

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“…Thus, overall there is no model which agrees with TDSE calculation in the complete intensity range. Accurate calculations using multi-configuration HartreeFock [192][193][194] for N 2 exist, but the results for absolute ionization yields have not been published so far. .5: Ionization as function of peak intensity for 800 nm laser is shown.…”

Section: Photon Energy Scanmentioning

confidence: 99%

Molecules in Strong Laser Fields

Corkum¹,

Dietrich²,

Strickland³

2008

Theoretical Femtosecond Physics

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A method for solving the time-dependent Schrödinger equation (TDSE) describing the electronic motion of the molecules exposed to very short intense laser pulses has been developed. The time-dependent electronic wavefunction is expanded in terms of a superposition of field-free eigenstates. The field-free eigenstates are calculated in two ways. In the first approach, which is applicable to two electron systems like H 2 , fully correlated field-free eigenstates are obtained in complete dimensionality using configuration-interaction calculation where the one-electron basis functions are built from B splines. In the second approach, which is even applicable to larger molecules, the field-free eigenstates are calculated within the single-active-electron (SAE) approximation using density functional theory. In general, the method can be divided into two parts, in the first part the field-free eigenstates are calculated and then in the second part a time propagation for the laser pulse parameters is performed. The H 2 molecule is the testing ground for the implementation of both the methods. The reliability of the configuration interaction (CI) based method for the solution of TDSE (CI-TDSE) is tested by comparing results in the low-intensity regime to the prediction of lowest-order perturbation theory. Another test for the CI-TDSE method is in the united atom limit for the H 2 molecule. By selecting a very small value of the internuclear distance close to zero for the H 2 molecule, Helium atom is obtained. The results in this united-atom limit are compared to the existing results for Helium atom. Once the functionality and the reliability of the method is established, it is used for obtaining accurate results for molecular hydrogen exposed to intense laser fields. The results for the standard 800 nm Titanium-Sapphire laser and its harmonics at 400 nm and 266 nm are shown. The results for a scan over a wide range of incident photon energies as well as dependence on the internuclear distance are presented. The photoelectron spectra including above-threshold-ionization peaks is also demonstrated. The CI-TDSE results for H 2 are used for testing the validity of SAE approximation. In strong field physics, there are models based on the SAE approximation. Most popular are the Ammosov-Delone-Krainov (ADK) model, a molecular version of the ADK model called MO-ADK (MO stands for molecular orbital) and the strong field approximation (SFA). The validity of the second method for the solution of TDSE in SAE approximation is investigated by applying it to H 2 molecule where the exact two-electron results were already calculated using CI-TDSE. The SAE method uses density-functional-theory (DFT) for the description of field-free eigenstates and is thus abbreviated as DFT-SAE-TDSE. Since DFT is used for the calculation of field-free states, different functionals were also tested. The validity of MO-ADK model is also investigated. After establishing the DFT-SAE-TDSE method, the first excited state B 1 Σ + u of H 2 is studied over a large...

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“…to a version thereof with a screened interaction potential [37]. Some works have also investigated models of reduced dimensionality, see e.g.…”

Section: Introductionmentioning

confidence: 99%

Two-photon ionization of helium studied with the multiconfigurational time-dependent Hartree–Fock method

Hochstuhl

Bönitz

2011

The Journal of Chemical Physics

103

120

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The multiconfigurational time-dependent Hartree-Fock method (MCTDHF) is applied for simulations of the two-photon ionization of Helium. We present results for the single-and double ionization from the groundstate for photon energies in the non-sequential regime, and compare them to direct solutions of the Schrödinger equation using the time-dependent (full) Configuration Interaction method (TDCI). We find that the single-ionization is accurately reproduced by MCTDHF, whereas the double ionization results correctly capture the main trends of TDCI.

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Strong field ionization of linear molecules: a correlated three-dimensional calculation

Cited by 40 publications

References 20 publications

Time-dependent complete-active-space self-consistent-field method for multielectron dynamics in intense laser fields

Time-dependent complete-active-space self-consistent-field method for multielectron dynamics in intense laser fields

Molecules in Strong Laser Fields

Two-photon ionization of helium studied with the multiconfigurational time-dependent Hartree–Fock method

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