The strong field photoelectron spectroscopy of acetylene: Evidence for short-lived 4p gerade states via electric field-induced resonance-enhanced multiphoton ionization

摘要

We report the intense field photoelectron spectra of acetylene, excited using 780 nm, 135 fs radiation for intensities ranging from 5.7 to 8.6X10~(13) W cm~(-2). Three features observed at 1.59, 1,95, and 2.13 eV are repeated at higher energies throughout the spectra as above threshold ionization features. A method for analysis of the spectra and assignment of peak is presented, based on intensity dependent shifting of intermediate states and ponderomotive shifts of the ionization potential. We present evidence for the observation of previously unobserved gerade states in the region of 9.81-10.35 eV.