Bond-selective fragmentation of water molecules with intense, ultrafast, carrier envelope phase stabilized laser pulses

Abstract

Carrier envelope phase (CEP) stabilized pulses of intense 800 nm light of 5 fs duration are used to probe the dissociation dynamics of dications of isotopically-substituted water, HOD. HOD 2+ dissociates into either H + + OD + or D + + OH + . The branching ratio for these two channels is CEP-dependent; the OD + /OH + ratio (relative to that measured with CEP-unstabilized pulses) varies from 150% to over 300% at different CEP values, opening prospects of isotope-dependent control over molecular bond breakage. The kinetic energy released as HOD 2+ Coulomb explodes is also CEP-dependent. Formidable theoretical challenges are identified for proper insights into the overall dynamics which involve non-adiabatic field ionization from HOD to HOD + and, thence, to HOD 2+ via electron rescattering.