Contribution of resonance excitation on ionization of OCS molecules in strong laser field

Abstract

The resonant enhanced multiphoton ionization (REMPI) of OCS molecules has been studied by tracing the electron energy shift with the laser intensity dependent photoelectron energy spectra. We find that two excited states (1Δ and 1Π) have been involved in the ionization of OCS at 800 nm and the REMPI through a certain excited state can be selectively controlled by varying the laser intensity. Furthermore, the REMPIof OCS through 4sσ?Rydberg states at 400 nm laser fields has also been identified by angular distribution of electrons.