Quantum control of electron-proton symmetry breaking in dissociative ionization of H₂by intense laser pulses

Abstract

Forward and backward electron/proton ionization/dissociation spectra from one‐dimensional non‐Born‐Oppenheimer H2 molecule exposed to ultrashort intense laser pulses ( I=4×1014 W/cm2, λ = 800 nm) have been computed by numerically solving the time‐dependent Schrödinger equation. The resulting above‐threshold ionization and above‐threshold dissociation spectra exhibit the characteristic forward‐backward asymmetry and sensitivity to the carrier‐envelope phase (CEP), particularly for high energies. A general framework for understanding CEP effects in the asymmetry of dissociative ionization of H2 has been established. It is found that the symmetry breaking of electron‐proton distribution with π periodic modulation occurs for all CEPs except for n20°−n30° ( n= integer) and the largest asymmetry coming from the CEP of n110°. At least one of the electron and proton distributions is asymmetric when measured simultaneously. Inspection of the nuclear and electron wave packet dynamics provides further information about the relative contribution of the gerade and ungerade states of normalH2+ to the dissociation channel and the time delay of electrons in asymmetric ionization. © 2014 Wiley Periodicals, Inc.

Charge Migration in Eyring, Walter and Kimball’s 1944 Model of the Electronically Excited Hydrogen-Molecule Ion

“…All of these observations are illustrated in Figures through , where, with one exception (the curve for the yield y z ( z 0 ) in Figure ), all are based on analytical expressions. This is in marked contrast with results for the EPDs during CM reported in refs − , all of which must be computed numerically.…”

“…The “correlated” initial state is therefore nonstationary. This is the view adopted by Cederbaum and associates. − However, the alternative scenario (ii) could produce the same initial state without the agency of electron correlation. Then CM would be described simply in terms of quantum interferences between the ground and first excited states.…”

“…In the present paper, however, we do take the oscillation literally in that our purpose is to illuminate the details of AACM in H 2 + within the restricted framework of the EWK model. Today, more than 70 years after EWK’s model of charge migration appeared, taking it literally is justified by the enormous amount of direct, as well as indirect, evidence that has accumulated over the past 20 years, starting from the first conjectures derived from experiments by the group of Weinkauf and Schlag, − followed by pioneering theoretical developments, in particular by the groups and partners of Levine and Remacle, − Cederbaum, − Bandrauk, − Fujimura, Kono, and Lin, − and several others, − including our own group and collaborators. − A recent milestone is the first joint experimental and theoretical study of AACM in the small linear iodo-acetylenic ion HCCI + in a quasi field-free environment (see also refs , , and ).…”

Controlling quantum wave packet of electronic motion on field‐dressed Coulomb potential of by carrier‐envelope phase‐dependent strong field laser pulses

“…Within a non‐Born‐Oppenheimer formalism, a time‐dependent Schrödinger equation for the H 2 molecule in a linearly polarized laser field [34] can be written as where is the mass of a nucleus, R is the relative H–H internuclear distance, z i is the coordinate of an electron i with respect to the nuclear center of mass, a = 0.7 and b = 1.2375 are parameter values chosen for the soft‐core Coulomb potential to reproduce accurately the first three Coulomb potentials of H 2 . Instead of the four‐dimensional numerical calculation that was performed previously [34], the current work includes a full range of the laser parameter in the five‐dimensional calculation, varying simultaneously with the electronic and nuclear coordinates, and time. The re...…”

“…Numerically solving for Equation (1) requires the electronic‐nuclear wave packet to be propagated with time intervals . It can be achieved by using the second‐order split operator technique [34, 38] as follows by adding a damping potential V damp and a time‐step of a.u. is used.…”