Revealing Orbital Dependent Quantum Interference Of O-2 Underlying Channel-Resolved Strong-Field Spectroscopies

We study the molecular orbital dependent tunneling ionization and quantum interference during laser-driven rescattering electron wavepacket of O-2 by performing the channel-resolved photoion and photoelectron measurements. The shifted above threshold ionization electron spectra demonstrate that direct ionization of HOMO-2 to the excited cation state contributes significantly to the generation of fragment ions, while the parent ions are generated from tunneling ionization of highest occupied molecular orbital (HOMO). Furthermore, the destructive and constructive interferences between different rescattering orbits from strong-field ionization of HOMO and HOMO-2 are confirmed by the measured channel and angle-resolved photoelectron momentum distribution.