Correlation between a photoelectron and a fragment ion in dissociative ionization of ethanol in intense near-infrared laser fields

Abstract

The two dissociative ionization channels of ethanol (C2H5OH) induced by an intense near-infrared laser pulse (λ ~ 783 nm), C2H5OH → CH2OH(+) + CH3 + e(-) and C2H5OH → C2H5(+) + OH + e(-), are investigated using photoelectron-photoion coincidence method. It is shown that both the electronic ground state and the first electronically excited state of C2H5OH(+) are produced at the moment of photoelectron emission. From the observed correlation between the electronic states of C2H5OH(+) prepared at the moment of photoelectron emission and the kinetic energy release of the fragment ions, it is revealed that C2H5OH(+) prepared in the electronic ground state at the photoelectron emission gains larger internal energy in the end than that prepared in the electronically excited state. The averaged internal energy of C2H5OH(+) just before the dissociation is found to increase when the laser field intensity increases from 9 to 23 TW∕cm(2) and when the laser pulse duration increases from 35 to 800 fs.