Quantum Control of Electron-Proton Symmetry Breaking in Dissociative Ionization of H2 by Intense Laser Pulses

Forward and backward electron/proton ionization/dissociation spectra from one-dimensional non-Born-Oppenheimer H-2 molecule exposed to ultrashort intense laser pulses (I=4x10(14) W/cm(2), lambda=800 nm) have been computed by numerically solving the time-dependent Schrodinger 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 H-2 has been established. It is found that the symmetry breaking of electron-proton distribution with pi-periodic modulation occurs for all CEPs except for n20 degrees-n30 degrees (n= integer) and the largest asymmetry coming from the CEP of n110 degrees. 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 H-2(+) to the dissociation channel and the time delay of electrons in asymmetric ionization. (c) 2014 Wiley Periodicals, Inc.