Two-Color Fields Induce New Peak in H₂⁺ Fragmentation

Researchers have identified a high-energy peak in the proton kinetic-energy-release spectrum of dissociating hydrogen molecular ions, a finding made possible through the use of orthogonal two-color laser fields. This peak was absent in simulations using single-color, linearly polarized light, indicating a significant alteration in fragmentation dynamics when employing these more complex field geometries. The yield of this peak can be coherently controlled by varying the relative carrier-envelope phase of the perpendicular field component, demonstrating a new method for precise manipulation of molecular fragmentation. Further analysis reveals the perpendicular field disrupts typical energy-sharing patterns in the main dissociation channel, shifting the process towards more complex multichannel dynamics and rotating fragment angular distributions away from the principal axis. The hydrogen molecular ion, the simplest molecule containing one electron and two protons, is a benchmark system for studying molecular dynamics in intense laser fields Krausz and Ivanov…