Time-dependent multiconfiguration theory for describing molecular dynamics in diatomic-like molecules

Controlling the Ultrafast Dynamics of HD+ by the Carrier-Envelope Phases of an Ultrashort Laser Pulse: A Quasi-Classical Dynamics Study

A theoretical study on the coupled electron-nuclear dynamics of HD⁺ molecular ions under ultrashort, intense laser pulses is performed by employing a well-established quasi-classical model. The influence of the laser carrier-envelope phase on various channel (H + D⁺, D + H⁺, and H⁺ + D⁺) probabilities is investigated at different laser field intensities. The carrier-envelope phase is found to govern the dissociation (H + D⁺ and D + H⁺) and Coulomb explosion (H⁺ + D⁺) channel probabilities. The kinetic energy release distributions of the fragments are also found to be sensitive to the carrier-envelope phase of the laser pulse. Our results are in agreement with the previously reported quantum dynamics studies and experiments.

Absolute carrier-envelope-phase dependences of single and double ionization of methanol in a near-IR few-cycle laser field

We investigate the carrier-envelope phase (CEP) dependences of the single and double ionization processes of methanol (CH₃OH) in an intense near-IR few-cycle laser field (2.1 × 10¹⁴ W/cm²) by the asymmetry in the ejection direction of CH₃ ⁺ for the non-hydrogen migration channels and CH₂ ⁺ for the hydrogen migration channels created through the C-O bond breaking after the ionization. Based on the absolute CEP values at the laser-molecule interaction point, calibrated by the method using intense few-cycle circularly polarized laser pulses [Fukahori et al., Phys. Rev. A 95, 053410-1-053410-14 (2017)], we confirm that methanol cations are produced by tunnel ionization and methanol dications are produced by the recollisional double ionization. We obtain the phase offset for the double ionization accompanying no hydrogen migration to be 1.85π as the absolute CEP at which the extent of the asymmetry becomes maximum. We interpret the phase shift of 0.85π from the phase offset of 1.0π for the tunnel ionization, estimated by a tunnel ionization model incorporating the chemical bond asymmetry, as the corresponding time delay associated with the electron recollisional ionization. The positive phase shift of 0.13π for the single ionization in the non-hydrogen migration channel is interpreted as the additional time (165 as) with which a methanol cation can be excited electronically prior to the decomposition. The additional phase shift of 0.22π for the single ionization in the hydrogen migration channel is interpreted as the additional time (280 as) required for a methanol cation to be excited electronically leading to the hydrogen migration prior to the decomposition.

A fully general time-dependent multiconfiguration self-consistent-field method for the electron–nuclear dynamics

A time-dependent multiconfiguration self-consistent-field method for a system consisting of arbitrarily different kinds and numbers of interacting fermions and bosons.

SOLVING THE SINGLE LAYER MULTICONFIGURATION TIME-DEPENDENT HARTREE–FOCK EQUATION IN SECOND QUANTIZATION REPRESENTATION BASED ON A DECOMPOSITION OF THE OVERALL FOCK SPACE

Very recently, the multilayer multiconfiguration time-dependent Hartree (MCTDH) method based on a decomposition of the overall Fock space in second quantization representation was proposed [Wang H, Thoss M, J Chem Phys131:024114, 2009], and they have presented demonstrative numerical example on vibrationally coupled electron transport. Followed by the thinking, the strategies of the implement of the theory to deal with multielectron dynamics with consideration coulomb interaction were discussed in detail. Some demonstrative calculations have been carried out by using the single layer MCTDHF method. The influences of the different choice way of initial condition, such as the species of basis function, the type of decomposition of the full Fock space, the choice of the spin orbitals, the number of the single particle function and so on, on the imaginary time propagation are mainly studied. The bridge between the generalized theory and the calculation application has been set up.

Classical dynamics of laser-driven D₃⁺

A classical model of the triatomic D₃⁺ molecule subjected to an intense, few-cycle laser pulse is introduced. The model is capable of describing the laser-induced correlated motion of both electrons and nuclei in three dimensions, and allows us to follow the motion of the two electrons and three deuterons from the initial field-free state, during the pulse, and until the bond breaking into the final fragments. By averaging over many trajectories, we calculate the relative yields of the ionization and dissociation channels, as well as the kinetic energy release (KER) from the fragment ions. A comparison with recent experimental KER spectra shows good qualitative agreement. In addition, we find a pathway in which an emitted electron recombines into a high-lying Rydberg state, resulting in D + D⁺ + D⁺ fragments with the same KER as in the D⁺ + D⁺ + D⁺ channel.